Filed Pursuant to Rule 424(b)(2)
Registration No. 333-214446

This preliminary prospectus supplement relates to an effective registration statement under the Securities Act of 1933, but the information in this preliminary prospectus supplement is not complete and may be changed. This preliminary prospectus supplement and the accompanying base prospectus are not an offer to sell and are not soliciting an offer to buy these securities in any jurisdiction where such offer or sale is not permitted.

SUBJECT TO COMPLETION, DATED AUGUST 7, 2018

PRELIMINARY PROSPECTUS SUPPLEMENT

(To Prospectus dated November 4, 2016)

$                     % SENIOR NOTES DUE 2028

$                     % SENIOR NOTES DUE 2048

We are offering $         aggregate principal amount of                 % Senior Notes due                  (the “2028 notes”) and $         aggregate principal amount of                 % Senior Notes due                  (the “2048 notes” and, together with the 2028 notes, the “notes”). Interest on the notes of each series will be paid semi-annually on                  and                  of each year, commencing on                 , 2019. The 2028 notes will mature on                 , 2028 and the 2048 notes will mature on                 , 2048, in each case unless redeemed prior to maturity.

We may redeem each series of notes, in whole or in part, at any time or from time to time prior to their maturity at the applicable redemption price described in this prospectus supplement under “Description of Notes — Optional Redemption.”

The notes will be our senior unsecured obligations, ranking equally in right of payment with our other existing and future senior indebtedness.

For a more detailed description of the notes, see “Description of Notes” beginning on page S-13.

The notes are new issues of securities with no established trading market. We do not currently intend to apply for listing of the notes on any securities exchange or for quotation on any automated quotation system.

Investing in the notes involves risks. See “Risk Factors” beginning on page S-7 of this prospectus supplement and on page 3 of the accompanying base prospectus.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus supplement and the accompanying base prospectus are truthful or complete. Any representation to the contrary is a criminal offense.

We expect that delivery of the notes offered hereby will be made in book-entry through the facilities of The Depository Trust Company for the accounts of its participants, including Clearstream Banking S.A. and Euroclear Bank SA/NV, as operator of the Euroclear System, on or about                 , 2018.

Joint Book-Running Managers

The date of this prospectus supplement is                 , 2018.

TABLE OF CONTENTS

Prospectus Supplement

Prospectus

This document is in two parts. The first part is this prospectus supplement, which describes the specific terms of this offering of notes. The second part is the accompanying base prospectus, which gives more general information, some of which may not apply to this offering of notes. Generally, when we refer only to the “prospectus,” we are referring to both parts combined. If the information about the notes offering varies between this prospectus supplement and the accompanying base prospectus, you should rely on the information in this prospectus supplement.

Any statement made in this prospectus or in a document incorporated or deemed to be incorporated by reference into this prospectus will be deemed to be modified or superseded for purposes of this prospectus to the extent that a statement contained in this prospectus or in any other subsequently filed document that is also incorporated by reference into this prospectus modifies or supersedes that statement. Any statement so modified or superseded will not be deemed, except as so modified or superseded, to constitute a part of this prospectus. Please read “Information Incorporated by Reference” on page S-39 of this prospectus supplement.

You should rely only on the information contained in or incorporated by reference into this prospectus supplement, the accompanying base prospectus and any free writing prospectus prepared by us or on our behalf relating to this offering of notes. Neither we nor any of the underwriters have authorized anyone to provide you with additional or different information. If anyone provides you with additional, different or inconsistent information, you should not rely on it. We and the underwriters are offering to sell the notes, and seeking offers to buy the notes, only in jurisdictions where such offers and sales are permitted. You should not assume that the information contained in this prospectus supplement, the accompanying base prospectus or any free writing prospectus is accurate as of any date other than the dates shown in these documents or that any information we have incorporated by reference herein is accurate as of any date other than the date of the applicable document incorporated by reference. Our business, financial condition, results of operations and prospects may have changed since those respective dates.

None of Western Gas Partners, LP, the underwriters or any of their respective representatives is making any representation to you regarding the legality of an investment in our notes by you under applicable laws. You should consult with your own advisors as to legal, tax, business, financial and related aspects of an investment in our notes.

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RATIO OF EARNINGS TO FIXED CHARGES AND RATIO OF EARNINGS TO COMBINED FIXED CHARGES AND PREFERRED UNIT DISTRIBUTIONS

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RISK FACTORS

An investment in our notes involves risk. Before making an investment in the notes offered hereby, you should carefully consider the risk factors below and those included under the caption “Risk Factors” beginning on page 3 of the accompanying base prospectus, as well as the risk factors included in our Annual Report on Form 10-K for the fiscal year ended December 31, 2017, together with all of the other information included or incorporated by reference in this prospectus supplement. If any of these risks were to occur, our business, financial condition or results of operations could be materially and adversely affected.

Risks Related to the Notes

Our significant indebtedness, and any future indebtedness, as well as the restrictions in our debt agreements may adversely affect our future financial and operating flexibility and our ability to service the notes.

As of June 30, 2018, after giving effect to this offering and the application of net proceeds as described in “Use of Proceeds,” our consolidated indebtedness would have been $                 billion, none of which is secured and consisting solely of our senior notes, including the notes offered hereby, and we would have been able to incur $1.5 billion of indebtedness under our revolving credit facility. Our substantial indebtedness and the additional debt we may incur in the future may adversely affect our liquidity and therefore our ability to make interest payments on the notes.

Among other things, our significant indebtedness may be viewed negatively by credit rating agencies, which could result in increased costs for us to access the capital markets. Any future downgrade of the debt issued by us or our subsidiaries could significantly increase our capital costs or adversely affect our ability to raise capital in the future.

Debt service obligations and restrictive covenants in our revolving credit facility and the indenture that will govern the notes may adversely affect our ability to finance future operations, pursue acquisitions and fund other capital needs. In addition, this leverage may make our results of operations more susceptible to adverse economic or operating conditions by limiting our flexibility in planning for, or reacting to, changes in our business and the industry in which we operate and may place us at a competitive disadvantage as compared to our competitors that have less debt.

The indenture that will govern the notes will permit us to incur additional debt, which would be equal in right of payment to the notes. If we incur any additional indebtedness, including trade payables, that ranks equally with the notes, the holders of that debt would be entitled to share ratably with you in any proceeds distributed in connection with any insolvency, liquidation, reorganization, dissolution or other winding up of us. This may have the effect of reducing the amount of proceeds paid to you. If new debt is added to our current debt levels, the related risks that we now face could intensify.

The notes will be our senior unsecured obligations and, as a result, the notes will be effectively junior to our future secured indebtedness, to the extent of the value of the collateral securing such indebtedness, and structurally subordinated to the indebtedness and other liabilities of our subsidiaries, other than subsidiaries that may guarantee the notes in the future.

The notes will be our senior unsecured obligations and will rank equally in right of payment with all of our other existing and future senior indebtedness, and will be structurally subordinated to the claims of all creditors, including trade creditors and tort claimants, of our subsidiaries, other than subsidiaries that may guarantee the notes in the future. In the event of the liquidation, dissolution, reorganization, bankruptcy or similar proceeding of the business of a subsidiary that is not a guarantor, creditors of that subsidiary, including trade creditors, would generally have the right to be paid in full before any distribution is made to us or the holders of the notes. Accordingly, there may not be sufficient funds remaining to pay amounts due on all or any of the notes. As of June 30, 2018, our subsidiaries had no debt for borrowed money owing to any unaffiliated third parties. However, the indenture will not prohibit such subsidiaries from incurring indebtedness in the future.

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In addition, because the notes and any future guarantees of the notes will be unsecured, holders of any secured indebtedness of ours or our subsidiaries would have claims with respect to the assets constituting collateral for such indebtedness that are senior to the claims of the holders of the notes. Currently, neither we nor any of our subsidiaries has any secured indebtedness. Although the indenture governing the notes will place some limitations on our ability to create liens securing indebtedness, there will be significant exceptions to these limitations that would allow us to secure significant amounts of indebtedness without equally and ratably securing the notes. If we or our subsidiaries incur secured indebtedness and such indebtedness is accelerated or we become subject to bankruptcy, liquidation or reorganization proceedings, our and our subsidiaries’ assets would be used to satisfy obligations with respect to the indebtedness secured thereby before any payment could be made on the notes. Consequently, any such secured indebtedness would effectively be senior to the notes and any future guarantees of the notes, to the extent of the value of the collateral securing such secured indebtedness. In that event, you may not be able to recover all the principal or interest you are due under the notes.

Any future subsidiary guarantees could be deemed fraudulent conveyances under certain circumstances, and in such event a court may try to subordinate or void the subsidiary guarantees.

The notes will not be guaranteed by any of our existing subsidiaries, although in the future one or more of our subsidiaries may do so. Under the federal bankruptcy laws and comparable provisions of state fraudulent transfer laws, a subsidiary guarantee could be voided, or claims in respect of a subsidiary guarantee could be subordinated to all other debts of that subsidiary guarantor if, among other things, the subsidiary guarantor, at the time it incurred the indebtedness evidenced by its subsidiary guarantee received less than reasonably equivalent value or fair consideration for the incurrence of such subsidiary guarantee and:

In addition, any payment by that subsidiary guarantor pursuant to its subsidiary guarantee could be voided and required to be returned to the subsidiary guarantor, or to a fund for the benefit of the creditors of the subsidiary guarantor. The measures of insolvency for purposes of these fraudulent transfer laws will vary depending upon the law applied in any proceeding to determine whether a fraudulent transfer has occurred. Generally, however, a subsidiary guarantor would be considered insolvent if:

We will make only limited covenants in the indenture that will govern the notes and these limited covenants may not protect your investment.

The indenture that will govern the notes will not:

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The indenture also will permit us and our subsidiaries to incur additional indebtedness, including secured indebtedness, that could effectively rank senior to the notes, and to engage in leaseback arrangements, subject to certain limitations. Any of these actions could adversely affect our ability to make principal and interest payments on the notes.

We have a holding company structure in which our subsidiaries conduct our operations and own our operating assets.

We are a holding company, and our subsidiaries conduct all of our operations and own all of our operating assets. We do not have significant assets other than equity in our subsidiaries and equity investees. As a result, our ability to make required payments on the notes depends on the performance of our subsidiaries and their ability to distribute funds to us. The ability of our subsidiaries to make distributions to us may be restricted by, among other things, credit instruments, applicable state business organization laws and other laws and regulations. If our subsidiaries are prevented from distributing funds to us, we may be unable to pay all the principal and interest on the notes when due.

Your ability to transfer the notes at a time or price you desire may be limited by the absence of an active trading market, which may not develop.

Although we have registered this offering of the notes under the Securities Act of 1933, as amended (the “Securities Act”), we do not intend to apply for listing of either series of notes on any securities exchange or for quotation of either series of notes in any automated dealer quotation system. In addition, although the underwriters have informed us that they intend to make a market in the notes, as permitted by applicable laws and regulations, they are not obligated to make a market in the notes, and they may discontinue their market-making activities at any time without notice. An active market for the notes does not currently exist and may not develop or, if developed, may not continue. In the absence of an active trading market, you may not be able to transfer the notes within the time or at the price you desire.

We do not have the same flexibility as other types of organizations to accumulate cash, which may limit cash available to service the notes or to repay them at maturity.

Unlike a corporation, our partnership agreement requires us to distribute, on a quarterly basis, 100% of our available cash to our unitholders of record and our general partner. The amount of available cash generally is all cash on hand at the end of the quarter, plus, at the discretion of our general partner, working capital borrowings made subsequent to the end of such quarter, less the amount of cash reserves established by our general partner to provide for the proper conduct of our business, including reserves to fund future capital expenditures; to comply with applicable laws, debt instruments or other agreements; or to provide funds for distributions to our unitholders and to our general partner for any one or more of the next four quarters. Our general partner determines the amount and timing of such distributions and has broad discretion to establish and make additions to our reserves or the reserves of our operating subsidiaries in amounts it determines, in its reasonable discretion.

Although our payment obligations to our unitholders are subordinate to our payment obligations to you, the value of our common units may decrease with decreases in the amount we distribute per unit. Accordingly, if we experience a liquidity problem in the future, the value of our common units may decrease, and we may not be able to issue equity to recapitalize or otherwise improve our liquidity.

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We may not be able to generate sufficient cash to service all of our indebtedness, including the notes and our indebtedness under our revolving credit facility, and we may be forced to take other actions to satisfy our obligations under our indebtedness, which may not be successful.

Our ability to make scheduled payments on or to refinance our debt obligations depends on our financial and operating performance, which is subject to prevailing economic and competitive conditions and to certain financial, business and other factors beyond our control. We cannot assure you that we will maintain a level of cash flows from operating activities sufficient to permit us to pay the principal, premium, if any, and interest on our indebtedness.

If our cash flows and capital resources are insufficient to fund our debt service obligations, we may be forced to reduce or delay capital expenditures, sell assets or operations, seek additional capital or restructure or refinance our indebtedness, including the notes. We cannot assure you that we would be able to take any of these actions, that these actions would be successful and would permit us to meet our scheduled debt service obligations or that these actions would be permitted under the terms of our existing or future debt agreements, including our credit agreement and the indenture that will govern the notes. For example, our revolving credit facility contains restrictions on our ability to dispose of assets. We may not be able to consummate asset dispositions, and any proceeds may not be adequate to meet any debt service obligations then due. See “Description of Notes.”

The credit and risk profile of our general partner and its indirect owner could adversely affect our credit ratings and profile.

The credit and business risk profiles of our general partner and its indirect owner, Anadarko, may be factors in credit evaluations of us due to the control of our general partner and the significant influence of Anadarko over our business activities, including our cash distributions, acquisition strategy and business risk profile. Another factor that may be considered is the financial condition of our general partner and Anadarko, including the degree of their financial leverage and their dependence on cash flow from us to service their indebtedness.

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USE OF PROCEEDS

We expect to receive net proceeds from this offering of approximately $         million after deducting the underwriting discount and estimated offering expenses payable by us.

We intend to use the net proceeds from this offering to repay our maturing 2018 notes, repay amounts outstanding under our revolving credit facility, and for general partnership purposes, including the funding of capital expenditures.

The 2018 notes mature on August 15, 2018 and bear interest at a rate of 2.600% per annum.

As of August 6, 2018, borrowings outstanding under our revolving credit facility were $60.0 million and had a weighted average interest rate of approximately 3.38%. The revolving credit facility bears interest at LIBOR, plus applicable margins ranging from 1.00% to 1.50%, or at an alternate base rate equal to the greatest of (a) the Prime Rate, (b) the Federal Funds Effective Rate plus 0.50%, or (c) LIBOR plus 1.0%, in each case plus applicable margins ranging from zero to 0.50%, based on our senior unsecured debt rating. The outstanding borrowings under our revolving credit facility were incurred to fund capital expenditures and for general partnership purposes. For a detailed description of our revolving credit facility, please read “Management’s Discussion and Analysis of Financial Condition and Results of Operations — Results of Operations — Liquidity and Capital Resources — Debt and credit facility — Revolving credit facility” in our Annual Report on Form 10-K for the year ended December 31, 2017, which is incorporated by reference into this prospectus.

Affiliates of each of the underwriters are holders of the 2018 notes or lenders under our revolving credit facility and, as such, will receive a portion of the net proceeds from this offering pursuant to the repayment of such indebtedness. See “Underwriting — Relationships with Underwriters.”

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CAPITALIZATION

The following table sets forth our cash and cash equivalents and capitalization as of June 30, 2018 on:

You should read our financial statements and notes thereto that are incorporated by reference into this prospectus supplement and the accompanying base prospectus for additional information about our capital structure.

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DESCRIPTION OF NOTES

You can find the definitions of certain terms used in this “Description of Notes” under “— Certain Definitions.” In this “Description of Notes,” the term “Partnership,” “us,” “our” or “we” refers only to Western Gas Partners, LP and not to any of its Subsidiaries. In this “Description of Notes,” references to the “2028 notes” are to the Senior Notes due 2028 offered hereby, references to the “2048 notes” are to the Senior Notes due 2048 offered hereby, and references to the “notes” are to the 2028 notes and 2048 notes together.

We have entered into a base indenture, dated as of May 18, 2011, among us, our prior subsidiary guarantors and Wells Fargo Bank, National Association, as trustee, pursuant to which we may issue multiple series of debt securities from time to time. Each series is issued under a supplement to the base indenture. We will issue the 2028 notes and 2048 notes as the ninth and tenth series, respectively, under the base indenture, as amended and supplemented by a supplemental indenture setting forth the specific terms of the notes (as so amended and supplemented, the “Indenture”).

The following description of the particular terms of the notes supplements the general description of the debt securities of the Partnership included in the accompanying base prospectus under the caption “Description of Debt Securities.” The notes will be a series of senior debt securities issued by the Partnership, as described herein and therein. You should review this “Description of Notes” together with the “Description of Debt Securities” included in the accompanying base prospectus. To the extent that this “Description of Notes” is inconsistent with the “Description of Debt Securities” in the accompanying base prospectus, this “Description of Notes” will control and replace the inconsistent “Description of Debt Securities” in the accompanying base prospectus.

We have summarized some of the material provisions of the notes and the Indenture below. The summary supplements the description of additional material provisions in the accompanying base prospectus that may be important to you. We also urge you to read the Indenture because it, and not this “Description of Notes,” defines your rights as a holder of notes. You may request copies of the base indenture and the supplemental indenture from us as set forth under “— Additional Information.” Capitalized terms defined in the accompanying base prospectus and the Indenture have the same meanings when used in this prospectus supplement. The terms of the notes include those expressly set forth in the Indenture and those made part of the Indenture by reference to the Trust Indenture Act of 1939, as amended.

The registered holder of a note will be treated as the owner of the note for all purposes. Only registered holders will have rights under the Indenture.

Brief Description of the Notes

The Notes

The notes will be:

Further Issuances

We may, from time to time after the closing of this offering, without notice to or the consent of the holders of the notes of either series or the trustee, increase the principal amount of either series of notes under the

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Indenture and issue such increased principal amount (or any portion thereof), in which case any additional notes so issued will have the same form and terms (other than the date of issuance, the price to the public and, under certain circumstances, the date from which interest thereon will begin to accrue and the initial interest payment date), and will carry the same right to receive accrued and unpaid interest, as the notes of that series previously issued, and such additional notes of that series will form a single series along with the notes of such series previously issued for all purposes under the Indenture.

Principal, Maturity and Interest

We will issue the 2028 notes in an initial aggregate principal amount of $            million, and we will issue the 2048 notes in an initial aggregate principal amount of $            million. The 2028 notes will mature on                 , 2028 and will bear interest at the annual rate of     % and the 2048 notes will mature on                 , 2048 and will bear interest at the annual rate of     %. Interest on each series of the notes will accrue from                 , 2018 and will be payable semi-annually in arrears on                  and                  of each year, commencing on                 , 2019. We will make each interest payment to the holders of record at the close of business on the                  and                  preceding such interest payment date (whether or not a business day). Interest will be computed and paid with respect to the notes on the basis of a 360-day year consisting of twelve 30-day months.

Form, Denomination and Registration of Notes

The notes will be issued in registered form, without interest coupons, in denominations of $2,000 and integral multiples of $1,000 in excess thereof. The notes will be represented by one or more global notes, as described below under “— Book-Entry Delivery and Settlement.”

Transfer and Exchange

A holder may transfer or exchange notes in accordance with the Indenture. No service charge will be imposed in connection with any transfer or exchange of any note, but we, the registrar and the trustee may require such holder, among other things, to furnish appropriate endorsements and transfer documents, and we may require such holder to pay any taxes and fees required by law or permitted by the Indenture. We are not required to transfer or exchange any notes selected for redemption. Also, we are not required to transfer or exchange any notes in respect of which a notice of redemption has been given or for a period of 15 days before any notice of redemption is sent.

Paying Agent and Registrar

The trustee will initially act as paying agent and registrar for the notes. We may change the paying agent or registrar without prior notice to the holders of the notes, and we or any of our Subsidiaries may act as paying agent or registrar; provided, however, that we will be required to maintain at all times an office or agency in The City of New York (which may be an office of the trustee or an affiliate of the trustee or the registrar or a co-registrar for the notes) where the notes may be presented for payment and where notes may be surrendered for registration of transfer or for exchange and where notices and demands to or upon us in respect of the notes and the Indenture may be served. We may also from time to time designate one or more additional offices or agencies where the notes may be presented or surrendered for any or all such purposes and may from time to time rescind such designations.

Future Subsidiary Guarantees

At the closing of this offering, the notes will not be guaranteed by any of our existing Subsidiaries. If in the future any of our Subsidiaries guarantees, becomes a borrower or guarantor under, or grants any Lien to secure any obligations pursuant to, our Revolving Credit Facility, then we will cause such Subsidiary to become a

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Guarantor by executing supplements to the Indenture and delivering such supplements to the trustee promptly (but in any event, within ten business days of the date on which it guaranteed or incurred such obligations or granted such Lien, as the case may be). In the event of a bankruptcy, liquidation or reorganization of any Subsidiary that does not guarantee the notes, such non-Guarantor Subsidiary will pay the holders of its Debt and its trade creditors before it will distribute any of its assets to us.

Any Subsidiary Guarantees will be joint and several obligations of the Guarantors. The obligations of each Guarantor under its Subsidiary Guarantee will be limited as necessary to prevent that Subsidiary Guarantee from constituting a fraudulent conveyance under applicable law. If a Subsidiary Guarantee is rendered voidable, it could be subordinated by a court to all other Debt (including guarantees and other contingent liabilities) of the applicable Guarantor, and, depending on the amount of such Debt, a Guarantor’s liability on its Subsidiary Guarantee could be reduced to zero.

The Indenture will limit the ability of a Guarantor to consolidate with or merge with or into any other Person, or sell, assign, transfer, lease, convey or otherwise dispose of all or substantially all of its properties or assets and the properties or assets of its Subsidiaries (taken as a whole with the properties or assets of such Guarantor) to another Person in one or more related transactions.

If any of our Subsidiaries guarantees the notes, its Subsidiary Guarantee will be released:

(1) in connection with any sale or other disposition of all or substantially all of the properties or assets of, or all of our direct or indirect limited partnership, limited liability company or other equity interests in, that Guarantor (including by way of merger or consolidation) to a Person that is not (either before or after giving effect to such transaction) an Affiliate of the Partnership;

(2) upon the merger of the Guarantor into us or any other Guarantor or the liquidation or dissolution of the Guarantor;

(3) upon legal defeasance or covenant defeasance as described below under the caption “— Discharge, Legal Defeasance and Covenant Defeasance” or upon satisfaction and discharge of the Indenture as described in the accompanying base prospectus under the caption “Description of Debt Securities — Satisfaction and Discharge”; or

(4) upon delivery of written notice to the trustee of the release of all guarantees or other obligations of the Guarantor under our Revolving Credit Facility.

If at any time following any release of a Guarantor from its guarantee of the notes pursuant to clause (4) in the preceding paragraph, the Guarantor again incurs obligations under our Revolving Credit Facility, then we will cause the Guarantor to again guarantee the notes in accordance with the Indenture.

Optional Redemption

We will have the right to redeem the notes of each series, in whole or in part, at any time before the applicable Par Call Date, at a redemption price equal to the greater of (1) 100% of the principal amount of the notes of such series to be redeemed and (2) the sum of the present values of the remaining scheduled payments of principal and interest on such notes that would have been due if such notes matured on the applicable Par Call Date (exclusive of interest accrued to the redemption date) discounted to the redemption date on a semiannual basis (assuming a 360-day year consisting of twelve 30-day months) at the Treasury Rate plus              basis points, with respect to the 2028 notes, and              basis points, with respect to the 2048 notes, plus, in either case, accrued interest, if any, on the principal amount being redeemed to such redemption date. On or after the applicable Par Call Date, the notes of each series will be redeemable and repayable, at our option, at any time in whole, or from time to time in part, at a price equal to 100% of the principal amount of the notes of such series to be redeemed plus accrued interest on the notes of such series to be redeemed to the date of redemption.

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“Comparable Treasury Issue” means the United States Treasury security selected by the Quotation Agent as having a maturity comparable to the remaining term of the notes to be redeemed, calculated as if the maturity date of the notes of such series were the applicable Par Call Date (the “Remaining Life”) that would be utilized at the time of selection and in accordance with customary financial practice, in pricing new issues of corporate debt securities of comparable maturity to the Remaining Life of such notes; provided, however, that if no maturity is within three months before or after the applicable Par Call Date, yields for the two published maturities most closely corresponding to such United States Treasury security will be determined and the Treasury Rate will be interpolated or extrapolated from those yields on a straight line basis rounding to the nearest month.

“Comparable Treasury Price” means, with respect to any redemption date for notes, (1) the average of four Reference Treasury Dealer Quotations for such redemption date after excluding the highest and lowest of all of the Reference Treasury Dealer Quotations or (2) if the Quotation Agent obtains fewer than four such Reference Treasury Dealer Quotations, the average of all such quotations.

“Par Call Date” means                 , 2028 for the 2028 notes (three months prior to the maturity date thereof) or                 , 2048 for the 2048 notes (six months prior to the maturity date thereof).

“Primary Treasury Dealer” means a U.S. government securities dealer in the City of New York.

“Quotation Agent” means the Reference Treasury Dealer appointed by us.

“Reference Treasury Dealer” means each of (i) Wells Fargo Securities, LLC and RBC Capital Markets, LLC and their respective successors so long as it is a Primary Treasury Dealer at the relevant time and, if it is not then a Primary Treasury Dealer, then a Primary Treasury Dealer selected by it, and (ii) a Primary Treasury Dealer selected by each of PNC Capital Markets LLC and U.S. Bancorp Investments, Inc. or their respective successors; provided that if any of the foregoing shall not be a Primary Treasury Dealer at such time and shall fail to select a Primary Treasury Dealer, then we will substitute therefor another Primary Treasury Dealer.

“Reference Treasury Dealer Quotation” means, with respect to each Reference Treasury Dealer as defined below and any redemption date, the average, as determined by the Quotation Agent, of the bid and asked prices for the Comparable Treasury Issue (expressed in each case as a percentage of its principal amount) quoted in writing to the Quotation Agent by such Reference Treasury Dealer at 5:00 p.m., New York City time, on the third business day preceding the redemption date.

“Treasury Rate” means, with respect to any redemption date, the rate per year equal to the semiannual equivalent yield to maturity of the Comparable Treasury Issue, calculated using a price for the Comparable Treasury Issue (expressed as a percentage of its principal amount) equal to the Comparable Treasury Price for such redemption date. We will calculate the Treasury Rate on the third business day preceding any redemption date and notify the trustee in writing of the Treasury Rate prior to the redemption.

Redemption Procedures

If fewer than all of the notes of either series are to be redeemed at any time, the notes of such series will be selected for redemption by the trustee on a pro rata basis, by lot or by such other method as the trustee deems appropriate (or, in the case of notes represented by a note in global form, by such method as DTC may require); provided, that no partial redemption of any note will occur if such redemption would reduce the principal amount of such note to less than $2,000. Notices of redemption with respect to the notes of either series shall be sent at least 15 but not more than 60 days before the redemption date to each holder of notes of such series to be redeemed at its registered address.

If any note is to be redeemed in part only, the notice of redemption that relates to such note shall state the portion of the principal amount thereof to be redeemed. A new note in principal amount equal to the unredeemed

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portion thereof will be issued in the name of the holder thereof upon cancellation of the original note. Notes called for redemption shall become due on the date fixed for redemption. Unless we default in payment of the redemption price, on and after the redemption date, interest will cease to accrue on the notes or portions of the notes called for redemption.

Open Market Purchases; No Mandatory Redemption or Sinking Fund

We may at any time and from time to time repurchase notes in the open market or otherwise, in each case without any restriction under the Indenture. We are not required to make mandatory redemption or sinking fund payments with respect to the notes.

No Personal Liability

Our partners (other than our general partner) and any directors, officers, employees, incorporators, shareholders, partners and members of our general partner will not be liable for:

By accepting the notes, each holder will be deemed to have waived and released all such liability. This waiver and release are part of the consideration for the issuance of the notes. This waiver may not be effective, however, to waive liabilities under the federal securities laws and it is the view of the SEC that such a waiver is against public policy.

Certain Covenants

Limitation on Liens

The Indenture will provide that while any notes remain outstanding, the Partnership will not, and will not permit any of its Principal Subsidiaries to, create, or permit to be created or to exist, any mortgage, lien, pledge, security interest, charge, adverse claim, or other encumbrance (“Lien”) upon any Principal Property of the Partnership or any of its Principal Subsidiaries, or upon any equity interests of any Principal Subsidiary, whether such Principal Property is, or equity interests are, owned on or acquired after the date of the Indenture, to secure any Debt, unless the notes then outstanding are equally and ratably secured by such Lien for so long as any such Debt is so secured, other than:

(1) purchase money mortgages, or other purchase money Liens of any kind upon property acquired by the Partnership or any Principal Subsidiary after the date of the Indenture, or Liens of any kind existing on any property or any equity interests at the time of the acquisition thereof (including Liens that exist on any property or any equity interests of a Person that is consolidated with or merged with or into the Partnership or any Principal Subsidiary or that transfers or leases all or substantially all of its properties or assets to the Partnership or any Principal Subsidiary), or conditional sales agreements or other title retention agreements and leases in the nature of title retention agreements with respect to any property hereafter acquired, so long as no such Lien shall extend to or cover any other property of the Partnership or such Principal Subsidiary;

(2) Liens upon any property of the Partnership or any Principal Subsidiary or any equity interests of any Principal Subsidiary existing as of the date of the initial issuance of the notes or upon the property or any equity interests of any entity, which Liens existed at the time such entity became a Subsidiary of the Partnership;

(3) Liens for taxes or assessments or other governmental charges or levies relating to amounts that are not yet delinquent or are being contested in good faith;

(4) pledges or deposits to secure: (a) any governmental charges or levies; (b) obligations under workers’ compensation laws, unemployment insurance and other social security legislation; (c) performance in connection

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with bids, tenders, contracts (other than contracts for the payment of money) or leases to which the Partnership or any Principal Subsidiary is a party; (d) public or statutory obligations of the Partnership or any Principal Subsidiary; and (e) surety, stay, appeal, indemnity, customs, performance or return-of-money bonds or pledges or deposits in lieu thereof;

(5) builders’, materialmen’s, mechanics’, carriers’, warehousemen’s, workers’, repairmen’s, operators’, landlords’ or other similar Liens, in the ordinary course of business;

(6) Liens created by or resulting from any litigation or proceeding that at the time is being contested in good faith by appropriate proceedings, including Liens relating to judgments thereunder as to which the Partnership or any Principal Subsidiary has not exhausted its appellate rights;

(7) Liens on deposits required by any Person with whom the Partnership or any Principal Subsidiary enters into forward contracts, futures contracts, swap agreements or other commodities contracts in the ordinary course of business and in accordance with established risk management policies and Liens in connection with leases (other than capital leases) made, or existing on property acquired, in the ordinary course of business;

(8) easements (including, without limitation, reciprocal easement agreements and utility agreements), zoning restrictions, rights-of-way, covenants, consents, reservations, encroachments, variations and other restrictions on the use of property or minor irregularities in title thereto, charges or encumbrances (whether or not recorded) affecting the use of real property and which are incidental to, and do not materially impair the use of such property in the operation of the business of the Partnership and its Subsidiaries, taken as a whole, or the value of such property for the purpose of such business;

(9) Liens in favor of the United States of America, any State, any foreign country or any department, agency or instrumentality or political subdivision of any such jurisdiction, to secure partial, progress, advance or other payments pursuant to any contract or statute or to secure any Debt incurred for the purpose of financing all or any part of the purchase price or the cost of constructing or improving the property subject to such Liens, including, without limitation, Liens to secure Debt of the pollution control or industrial revenue bond type;

(10) Liens of any kind upon any property acquired, constructed, developed or improved by the Partnership or any Principal Subsidiary (whether alone or in association with others) after the date of the Indenture that are created prior to, at the time of, or within 12 months after such acquisition (or in the case of property constructed, developed or improved, after the completion of such construction, development or improvement and commencement of full commercial operation of such property, whichever is later) to secure or provide for the payment of any part of the purchase price or cost thereof; provided that in the case of such construction, development or improvement the Liens shall not apply to any property theretofore owned by the Partnership or any Principal Subsidiary other than theretofore unimproved real property;

(11) Liens in favor of the Partnership, one or more Principal Subsidiaries, one or more wholly owned Subsidiaries of the Partnership or any of the foregoing in combination;

(12) the replacement, extension or renewal (or successive replacements, extensions or renewals), as a whole or in part, of any Lien, or of any agreement, referred to in the clauses above, or the replacement, extension or renewal of the Debt secured thereby (not exceeding the principal amount of Debt secured thereby, other than to provide for the payment of any underwriting or other fees related to any such replacement, extension or renewal, as well as any premiums owed on and accrued and unpaid interest payable in connection with any such replacement, extension or renewal); provided that such replacement, extension or renewal is limited to all or a part of the same property that secured the Lien replaced, extended or renewed (plus improvements thereon or additions or accessions thereto); or

(13) any Lien not excepted by the foregoing clauses; provided that immediately after the creation or assumption of such Lien the aggregate principal amount of Debt of the Partnership or any Principal Subsidiary

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secured by all Liens created or assumed under the provisions of this clause, together with all net sale proceeds from any Sale-Leaseback Transactions, subject to certain exceptions, shall not exceed an amount equal to 15% of the Consolidated Net Tangible Assets for the fiscal quarter that was most recently completed prior to the creation or assumption of such Lien.

Notwithstanding the foregoing, for purposes of making the calculation set forth in clause (13) of the preceding paragraph, with respect to any such secured Debt of a non-wholly owned Principal Subsidiary of the Partnership with no recourse to the Partnership or any wholly owned Principal Subsidiary thereof, only that portion of the aggregate principal amount of such secured Debt reflecting the Partnership’s pro rata ownership interest in such non-wholly owned Principal Subsidiary shall be included in calculating compliance herewith.

Limitation on Sale-Leaseback Transactions

The Indenture will provide that while any notes remain outstanding, the Partnership will not, and will not permit any of its Principal Subsidiaries to, engage in a Sale-Leaseback Transaction, unless:

(1) the Sale-Leaseback Transaction occurs within one year from the date of acquisition of the relevant Principal Property or the date of the completion of construction or commencement of full operations on such Principal Property, whichever is later, and the Partnership has elected to designate, as a credit against (but not exceeding) the purchase price or cost of construction of such Principal Property, an amount equal to all or a portion of the net sale proceeds from such Sale-Leaseback Transaction (with any such amount not being so designated to be applied as set forth in clause (2) below);

(2) the Partnership or such Principal Subsidiary would be entitled to incur Debt secured by a Lien on the Principal Property subject to the Sale-Leaseback Transaction in a principal amount equal to or exceeding the net sale proceeds from such Sale-Leaseback Transaction without equally and ratably securing the notes; or

(3) the Partnership or such Principal Subsidiary, within a 270-day period after such Sale-Leaseback Transaction, applies or causes to be applied an amount not less than the net sale proceeds from such Sale-Leaseback Transaction to (1) the prepayment, repayment, redemption or retirement of any unsubordinated Debt of the Partnership or any of its Subsidiaries (A) for borrowed money or (B) evidenced by bonds, debentures, notes or other similar instruments, or (2) invest in another Principal Property.

Reports

The Indenture will provide that so long as any notes are outstanding, the Partnership will:

Consolidation, Merger, Conveyance or Transfer

The Indenture will provide that the Partnership may not consolidate with or merge with or into any other Person, or sell, assign, transfer, lease, convey or otherwise dispose of all or substantially all of its properties or

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assets and the properties or assets of its Subsidiaries (taken as a whole with the properties or assets of the Partnership) to another Person in one or more related transactions, unless:

Upon the assumption of the Partnership’s obligations under the Indenture by a successor, the Partnership will be discharged from all obligations under the Indenture (except in the case of a lease).

Discharge, Legal Defeasance and Covenant Defeasance

The Indenture will provide that we may be:

The defeasance provisions of the Indenture described in the accompanying base prospectus will apply to the notes. See “Description of Debt Securities — Defeasance” in the accompanying base prospectus.

The Indenture will be subject to discharge with respect to the notes as described in the accompanying base prospectus under “Description of Debt Securities — Satisfaction and Discharge.”

Concerning the Trustee

The trustee will perform only those duties that are specifically set forth in the Indenture unless an event of default occurs and is continuing. If an event of default occurs and is continuing, the trustee will exercise the same degree of care and skill in the exercise of its rights and powers under the Indenture as a prudent man would exercise in the conduct of his own affairs. The trustee will be under no obligation to expend or risk its own funds or otherwise incur any financial liability in the performance of any of its duties under the Indenture, or in the exercise of any of its rights or powers.

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Notice

Notice to holders of the notes will be given by first-class mail at such holder’s address as it appears in the security register or, in the case of global notes, it will be given in accordance with the depositary’s applicable procedures.

Title

We, the Guarantors, if any, the trustee and any of our, any Guarantors’ or the trustee’s agents may treat the person in whose name the notes are registered as the owner of the notes, whether or not such notes may be overdue, for the purpose of making payment and for all other purposes.

Governing Law

The Indenture and the notes will be governed by, and construed in accordance with, the laws of the State of New York.

Additional Information

Anyone who receives this prospectus supplement may obtain a copy of each of the base indenture and the supplemental indentures without charge by writing to Western Gas Partners, LP, 1201 Lake Robbins Drive, The Woodlands, Texas 77380, Telephone (832) 636-6000.

Book-Entry Delivery and Settlement

Global Notes

We will issue the notes in the form of one or more permanent global notes in fully registered, book-entry form. The global notes will be deposited with or on behalf of The Depository Trust Company (the “DTC”) and registered in the name of Cede & Co., as nominee of DTC.

DTC, Clearstream and Euroclear

Beneficial interests in the global notes will be represented through book-entry accounts of financial institutions acting on behalf of beneficial owners as direct and indirect participants in DTC. Investors may hold interests in the global notes through either DTC (in the United States of America), Clearstream Banking S.A., Luxembourg (“Clearstream”), or Euroclear Bank SA/NV (the “Euroclear Operator”), as operator of the Euroclear System (in Europe) (“Euroclear”), either directly if they are participants of such systems or indirectly through organizations that are participants in such systems. Clearstream and Euroclear will hold interests on behalf of their participants through customers’ securities accounts in Clearstream’s and Euroclear’s names on the books of their U.S. depositaries, which in turn will hold such interests in customers’ securities accounts in the U.S. depositaries’ names on the books of DTC.

DTC has advised us as follows:

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We have provided the descriptions of the operations and procedures of DTC, Clearstream and Euroclear in this prospectus supplement solely as a matter of convenience. These operations and procedures are solely within the control of those organizations and are subject to change by them from time to time. None of us, the underwriters nor the trustee takes any responsibility for these operations or procedures, and you are urged to contact DTC, Clearstream and Euroclear or their participants directly to discuss these matters.

We expect that under procedures established by DTC:

The laws of some jurisdictions may require that purchasers of securities take physical delivery of those securities in definitive form. Accordingly, the ability to transfer interests in the notes represented by a global note to those persons may be limited. In addition, because DTC can act only on behalf of its participants, who in turn act on behalf of persons who hold interests through participants, the ability of a person having an interest in notes represented by a global note to pledge or transfer those interests to persons or entities that do not participate in DTC’s system, or otherwise to take actions in respect of such interest, may be affected by the lack of a physical definitive security in respect of such interest.

So long as DTC or its nominee is the registered owner of a global note, DTC or that nominee will be considered the sole owner or holder of the notes represented by that global note for all purposes under the Indenture and under the notes. Except as provided below, owners of beneficial interests in a global note will not be entitled to have notes represented by that global note registered in their names, will not receive or be entitled to receive physical delivery of definitive notes and will not be considered the owners or holders thereof under the Indenture or under the notes for any purpose, including with respect to the giving of any direction, instruction or approval to the trustee. Accordingly, each holder owning a beneficial interest in a global note must rely on the procedures of DTC and, if that holder is not a direct or indirect participant, on the procedures of the participant through which that holder owns its interest, to exercise any rights of a holder of notes under the Indenture or the global note.

None of us, the Guarantors, if any, the underwriters nor the trustee will have any responsibility or liability for any aspect of the records relating to or payments made on account of notes by DTC, Clearstream or Euroclear, or for maintaining, supervising or reviewing any records of those organizations relating to the notes.

Payments on the notes represented by the global notes will be made to DTC or its nominee, as the case may be, as the registered owner thereof. We expect that DTC or its nominee, upon receipt of any payment on the notes

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represented by a global note, will credit participants’ accounts with payments in amounts proportionate to their respective beneficial interests in the global note as shown in the records of DTC or its nominee. We also expect that payments by participants to owners of beneficial interests in a global note held through such participants will be governed by standing instructions and customary practice as is now the case with securities held for the accounts of customers registered in the names of nominees for such customers. The participants will be responsible for those payments.

Distributions on the notes held beneficially through Clearstream will be credited to cash accounts of its customers in accordance with its rules and procedures, to the extent received by the U.S. depositary for Clearstream.

Securities clearance accounts and cash accounts with the Euroclear Operator are governed by the Terms and Conditions Governing Use of Euroclear and the related Operating Procedures of the Euroclear System, and applicable Belgian law (collectively, the “Terms and Conditions”). The Terms and Conditions govern transfers of securities and cash within Euroclear, withdrawals of securities and cash from Euroclear, and receipts of payments with respect to securities in Euroclear. All securities in Euroclear are held on a fungible basis without attribution of specific certificates to specific securities clearance accounts. The Euroclear Operator acts under the Terms and Conditions only on behalf of Euroclear participants and has no record of or relationship with persons holding through Euroclear participants.

Distributions on the notes held beneficially through Euroclear will be credited to the cash accounts of its participants in accordance with the Terms and Conditions, to the extent received by the U.S. depositary for Euroclear.

Clearance and Settlement Procedures

Initial settlement for the notes will be made in immediately available funds. Secondary market trading between DTC participants will occur in the ordinary way in accordance with DTC rules and will be settled in immediately available funds. Secondary market trading between Clearstream customers and/or Euroclear participants will occur in the ordinary way in accordance with the applicable rules and operating procedures of Clearstream and Euroclear and will be settled using the procedures applicable to conventional eurobonds in immediately available funds.

Cross-market transfers between persons holding directly or indirectly through DTC, on the one hand, and directly or indirectly through Clearstream customers or Euroclear participants, on the other, will be effected in DTC’s system in accordance with DTC rules on behalf of the relevant European international clearing system by the U.S. depositary; however, such cross-market transactions will require delivery of instructions to the relevant European international clearing system by the counterparty in such system in accordance with its rules and procedures and within its established deadlines (European time). The relevant European international clearing system will, if the transaction meets its settlement requirements, deliver instructions to the U.S. depositary to take action to effect final settlement on its behalf by delivering or receiving the notes in DTC’s system, and making or receiving payment in accordance with normal procedures for same-day funds settlement applicable to DTC.

Clearstream customers and Euroclear participants may not deliver instructions directly to their U.S. depositaries.

Because of time-zone differences, credits of the notes received in Clearstream or Euroclear as a result of a transaction with a DTC participant will be made during subsequent securities settlement processing and dated the business day following the DTC settlement date. Such credits or any transactions in the notes settled during such processing will be reported to the relevant Clearstream customers or Euroclear participants on such business day. Cash received in Clearstream or Euroclear as a result of sales of the notes by or through a Clearstream customer

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or a Euroclear participant to a DTC participant will be received with value on the DTC settlement date but will be available in the relevant Clearstream or Euroclear cash account only as of the business day following settlement in DTC.

Although DTC, Clearstream and Euroclear have agreed to the foregoing procedures to facilitate transfers of the notes among participants of DTC, Clearstream and Euroclear, they are under no obligation to perform or continue to perform such procedures and such procedures may be changed or discontinued at any time.

Definitive Notes

We will issue definitive notes under the Indenture to each person that DTC identifies as the beneficial owner of the notes represented by a global note upon surrender by DTC of the global note only if:

Neither we nor the trustee will be liable for any delay by DTC, its nominee or any direct or indirect participant in identifying the beneficial owners of the related notes. We and the trustee may conclusively rely on, and will be protected in relying on, instructions from DTC or its nominee for all purposes, including with respect to the registration and delivery, and the respective principal amounts, of the notes to be issued.

Certain Definitions

“Consolidated Net Tangible Assets” means at any date of determination, the total amount of consolidated assets of the Partnership and its Subsidiaries after deducting therefrom (1) all current liabilities (excluding (a) any current liabilities that by their terms are extendable or renewable at the option of the obligor thereon to a time more than 12 months after the time as of which the amount thereof is being computed and (b) current maturities of long-term debt), and (2) the value (net of any applicable reserves) of all goodwill, trade names, trademarks, patents and other like intangible assets, all as set forth, or on a pro forma basis would be set forth, on the consolidated balance sheet of the Partnership and its Subsidiaries for the most recently completed fiscal quarter, prepared in accordance with generally accepted accounting principles in the United States.

“Debt” of any Person means, without duplication, (1) all indebtedness of such Person for borrowed money (whether or not the recourse of the lender is to the whole of the assets of such Person or only to a portion thereof), (2) all obligations of such Person evidenced by bonds, debentures, notes or other similar instruments, (3) all obligations of such Person in respect of letters of credit or other similar instruments (or reimbursement obligations with respect thereto), other than standby letters of credit, performance bonds and other obligations issued by or for the account of such Person in the ordinary course of business, to the extent not drawn or, to the extent drawn, if such drawing is reimbursed not later than the third Business Day following demand for reimbursement, (4) all obligations of such Person to pay the deferred and unpaid purchase price of property or services, except trade payables and accrued expenses incurred in the ordinary course of business, (5) all capitalized lease obligations of such Person, (6) all Debt of others secured by a Lien on any asset of such Person, whether or not such Debt is assumed by such Person (provided that if the obligations so secured have not been assumed in full by such Person or are not otherwise such Person’s legal liability in full, then such obligations

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shall be deemed to be in an amount equal to the greater of (a) the lesser of (i) the full amount of such obligations and (ii) the fair market value of such assets, as determined in good faith by the Board of Directors of such Person, which determination shall be evidenced by a Board Resolution, and (b) the amount of obligations as have been assumed by such Person or which are otherwise such Person’s legal liability), and (7) all Debt of others (other than endorsements in the ordinary course of business) guaranteed by such Person to the extent of such guarantee.

“guarantee” means a guarantee other than by endorsement of negotiable instruments for collection in the ordinary course of business, direct or indirect, in any manner including, without limitation, by way of a pledge of assets or through letters of credit or reimbursement agreements in respect thereof, of all or any part of any Debt. When used as a verb, “guarantee” has a correlative meaning.

“Guarantors” means any Subsidiary of the Partnership that becomes a Guarantor in accordance with the provisions of the Indenture.

“obligations” means any principal, premium, if any, interest (including interest accruing on or after the filing of any petition in bankruptcy or for reorganization, whether or not a claim for post-filing interest is allowed in such proceeding), penalties, fees, charges, expenses, indemnifications, reimbursement obligations, damages, guarantees, and other liabilities or amounts payable under the documentation governing any Debt or in respect thereto.

“Person” means any individual, corporation, partnership, joint venture, joint stock company, association, trust, unincorporated organization, limited liability company, government or any agency or political subdivision thereof or any other entity.

“Principal Property” means, whether currently owned or leased or subsequently acquired, any pipeline, gathering system, terminal, storage facility, processing plant or other plant or facility located in the United States of America or any territory or political subdivision thereof owned or leased by the Partnership or any of its Subsidiaries and used in the transportation, distribution, terminalling, gathering, treating, processing, marketing or storage of natural gas and natural gas liquids and propane except (1) any property or asset consisting of inventories, furniture, office fixtures and equipment (including data processing equipment), vehicles and equipment used on, or useful with, vehicles (but excluding vehicles that generate transportation revenues) and (2) any such property or asset, plant or terminal which, in the good faith opinion of the Board of Directors of the General Partner as evidenced by resolutions of the Board of Directors of the General Partner, is not material in relation to the activities of the Partnership and its Subsidiaries, taken as a whole.

“Principal Subsidiary” means any of the Partnership’s Subsidiaries that owns or leases, directly or indirectly, a Principal Property.

“Revolving Credit Facility” means the Third Amended and Restated Revolving Credit Agreement, dated as of February 15, 2018, among the Partnership, Wells Fargo Bank, National Association, as the administrative agent and the lenders party thereto, as amended, restated, refinanced, replaced or refunded from time to time.

“Sale-Leaseback Transaction” means the sale or transfer by the Partnership or any Principal Subsidiary of any Principal Property to a Person (other than the Partnership or a Principal Subsidiary) and the taking back by the Partnership or any Principal Subsidiary, as the case may be, of a lease of such Principal Property.

“Subsidiary” means, as to any Person, (1) any corporation, association or other business entity (other than a partnership or limited liability company) of which more than 50% of the outstanding capital stock having ordinary voting power is at the time owned or controlled, directly or indirectly, by such Person or one or more of the other Subsidiaries of such Person or (2) any general or limited partnership or limited liability company, (a) the sole general partner or member of which is the Person or a Subsidiary of the Person or (b) if there is more

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than one general partner or member, either (i) the only managing general partners or managing members of such partnership or limited liability company are such Person or Subsidiaries of such Person or (ii) such Person owns or controls, directly or indirectly, a majority of the outstanding general partner interests, member interests or other voting equities of such partnership or limited liability company, respectively.

“Subsidiary Guarantee” means any guarantee by a Guarantor of the Partnership’s obligations under the Indenture and on the notes.

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CERTAIN U.S. FEDERAL INCOME TAX CONSIDERATIONS

The following discussion summarizes certain U.S. federal income tax considerations that may be relevant to the acquisition, ownership and disposition of the notes. This discussion is based upon the provisions of the Internal Revenue Code of 1986, as amended (the “Code”), applicable U.S. Treasury regulations promulgated thereunder, judicial authority and administrative interpretations, all as of the date of this document, and all of which are subject to change, possibly with retroactive effect, or are subject to different interpretations. We cannot assure you that any change in law will not significantly alter the tax considerations that we describe in this discussion. In addition, we cannot assure you that the Internal Revenue Service (the “IRS”) will not challenge one or more of the tax consequences described in this discussion, and we have not obtained, nor do we intend to obtain, a ruling from the IRS or an opinion of counsel with respect to the U.S. federal income tax consequences of acquiring, owning or disposing of the notes.

This discussion is limited to holders who purchase the notes in this offering for cash at a price equal to the issue price of the notes (i.e., the first price at which a substantial amount of the notes is sold for cash other than to bond houses, brokers or similar persons or organizations acting in the capacity of underwriters, placement agents or wholesalers) and who hold the notes as capital assets (generally, property held for investment). This discussion does not address any U.S. federal tax considerations other than U.S. federal income tax considerations (such as estate and gift tax considerations), or the tax considerations arising under the laws of any foreign, state, local or other jurisdiction or any income tax treaty. In addition, this discussion does not address all tax considerations that may be important to a particular holder in light of the holder’s circumstances, or to certain categories of investors that may be subject to special rules, such as:

If an entity or arrangement treated as a partnership for U.S. federal income tax purposes holds notes, the U.S. federal income tax treatment of a partner of the partnership generally will depend upon the status of the partner and the activities of the partnership and upon certain determinations made at the partner level. If you are a partner of a partnership considering an investment in the notes, you are urged to consult your own tax advisor about the U.S. federal income tax consequences of acquiring, holding and disposing of the notes.

Under recently enacted legislation, U.S. holders that use an accrual method of accounting for U.S. federal income tax purposes may be required to include certain amounts in income no later than the time such amounts are reflected on certain financial statements. Although the precise application of this rule is unclear at this time, it may require the accrual of income earlier than would be the case under the general tax rules described below. U.S. holders that use an accrual method of accounting are urged to consult their tax advisors regarding the potential applicability of this legislation to their particular situation.

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INVESTORS CONSIDERING THE PURCHASE OF NOTES ARE URGED TO CONSULT THEIR OWN TAX ADVISORS REGARDING THE APPLICATION OF THE U.S. FEDERAL INCOME TAX LAWS TO THEIR PARTICULAR SITUATIONS AS WELL AS ANY TAX CONSEQUENCES OF THE ACQUISITION, OWNERSHIP AND DISPOSITION OF THE NOTES UNDER OTHER U.S. FEDERAL TAX LAWS OR UNDER THE LAWS OF ANY STATE, LOCAL OR FOREIGN JURISDICTION OR UNDER ANY APPLICABLE INCOME TAX TREATY.

Certain Additional Payments

In certain circumstances (see “Description of Notes — Optional Redemption”), we may be obligated to pay amounts on the notes that are in excess of stated interest or principal on the notes. These potential payments may implicate the provisions of the U.S. Treasury regulations relating to “contingent payment debt instruments.” We do not intend to treat the possibility of paying such additional amounts as causing the notes to be treated as contingent payment debt instruments. It is possible that the IRS may take a different position, in which case, if such position is sustained, a holder might be required to accrue ordinary interest income at a higher rate than the stated interest rate and to treat as ordinary income rather than capital gain any gain realized on the taxable disposition of the notes. The remainder of this discussion assumes that the notes will not be treated as contingent payment debt instruments. You are encouraged to consult your own tax advisor regarding the possible application of the contingent payment debt instrument rules to the notes.

Tax Consequences to U.S. Holders

The following summary will apply to you if you are a U.S. holder of the notes. You are a “U.S. holder” for purposes of this discussion if you are a beneficial owner of a note and you are for U.S. federal income tax purposes:

Interest on the Notes

Interest on the notes generally will be taxable to you as ordinary income at the time it is received or accrued in accordance with your regular method of accounting for U.S. federal income tax purposes.

Disposition of the Notes

You will generally recognize capital gain or loss on the sale, redemption, exchange, retirement or other taxable disposition of a note equal to the difference, if any, between the proceeds you receive (excluding any proceeds attributable to accrued but unpaid interest, which will be taxable as ordinary interest income to the extent you have not previously included such amounts in income) and your adjusted tax basis in the note. The proceeds you receive will include the amount of any cash and the fair market value of any other property received for the note. Your adjusted tax basis in the note will generally equal the amount you paid for the note. Any gain or loss will be long-term capital gain or loss if you held the note for more than one year at the time of the sale, redemption, exchange, retirement or other taxable disposition. Long-term capital gains of individuals, estates and trusts currently are eligible for reduced rates of U.S. federal income tax. The deductibility of capital losses may be subject to limitation.

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Information Reporting and Backup Withholding

Information reporting generally will apply to payments of interest on, and the proceeds of the sale or other disposition (including a redemption, exchange or retirement) of, notes held by you, and backup withholding will apply to such payments unless you provide to the applicable withholding agent your taxpayer identification number, certified under penalties of perjury, as well as certain other information or otherwise establish an exemption from backup withholding. Backup withholding is not an additional tax. Any amount withheld under the backup withholding rules is allowable as a credit against your U.S. federal income tax liability, if any, and a refund may be obtained from the IRS if the amounts withheld exceed your actual U.S. federal income tax liability and you timely provide the required information or appropriate claim form to the IRS.

Tax Consequences to Non-U.S. Holders

The following summary will apply to you if you are a non-U.S. holder of notes. You are a “non-U.S. holder” for purposes of this discussion if you are a beneficial owner of notes that is, for U.S. federal income tax purposes, an individual, corporation, estate or trust that is not a U.S. holder.

Interest on the Notes

Subject to the discussion of backup withholding and FATCA withholding, below, payments to you of interest on the notes generally will not be subject to U.S. federal income tax and will be exempt from withholding of U.S. federal income tax under the “portfolio interest” exemption if you properly certify as to your foreign status, as described below, and:

The portfolio interest exemption generally applies only if you also appropriately certify as to your foreign status. You can generally meet the certification requirement by providing a properly executed IRS Form W-8BEN or IRS Form W-8BEN-E (or other applicable or successor form) to the applicable withholding agent. If you hold the notes through a financial institution or other agent acting on your behalf, you may be required to provide appropriate certifications to the agent. Your agent will then generally be required to provide appropriate certifications to the applicable withholding agent, either directly or through other intermediaries. Special rules apply to foreign partnerships, estates and trusts, and in certain circumstances certifications as to the foreign status of partners, trust owners or beneficiaries may have to be provided to the applicable withholding agent. In addition, special rules apply to qualified intermediaries that enter into withholding agreements with the IRS.

If you cannot satisfy the requirements described above, payments of interest made to you will be subject to U.S. federal withholding tax at a 30% rate, unless (i) you provide the applicable withholding agent with a properly executed IRS Form W-8BEN or IRS Form W-8BEN-E (or other applicable or successor form) claiming an exemption from (or a reduction of) withholding under the benefits of an income tax treaty, or (ii) the payments of such interest are effectively connected with your conduct of a trade or business in the United States (and, if required by an applicable income tax treaty, are attributable to a permanent establishment maintained by you in the United States) and you meet the certification requirements described below. (See “— Income or Gain Effectively Connected with a U.S. Trade or Business.”)

The certifications described above and below must be provided to the applicable withholding agent prior to the payment of interest and must be updated periodically. If you do not timely provide the applicable withholding

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agent with the required certification, but you qualify for a reduced rate under an applicable income tax treaty, you may obtain a refund of any excess amounts withheld if you timely provide the required information or appropriate claim form to the IRS.

Disposition of the Notes

Subject to the discussion of backup withholding and FATCA withholding, below, you generally will not be subject to U.S. federal income tax on any gain (excluding any amount attributable to accrued and unpaid interest, which generally will be treated as interest and may be subject to the rules discussed above in “— Interest on the Notes”) realized on the sale, redemption, exchange, retirement or other taxable disposition of a note unless:

If your gain is described in the first bullet point above, you generally will be subject to U.S. federal income tax in the manner described under “— Income or Gain Effectively Connected with a U.S. Trade or Business.” If you are a non-U.S. holder described in the second bullet point above, you will be subject to a flat 30% (or lower applicable income tax treaty rate) U.S. federal income tax on the gain derived from the sale or other disposition, which may be offset by certain U.S. source capital losses.

Income or Gain Effectively Connected with a U.S. Trade or Business

If any interest on the notes or gain from the sale, redemption, exchange, retirement or other taxable disposition of the notes is effectively connected with a U.S. trade or business conducted by you (and, if required by an applicable income tax treaty, you maintain a permanent establishment in the United States to which such interest or gain is attributable), then the interest income or gain will be subject to U.S. federal income tax at regular graduated income tax rates generally in the same manner as if you were a U.S. holder. Effectively connected interest income will not be subject to U.S. federal withholding tax if you satisfy certain certification requirements by providing to the applicable withholding agent a properly executed IRS Form W-8ECI (or successor form). In addition, if you are a corporation, that portion of your earnings and profits that is effectively connected with your U.S. trade or business may also be subject to a “branch profits tax” at a 30% rate, unless an applicable income tax treaty provides for a lower rate. For this purpose, interest received on a note and gain recognized on the disposition of a note will be included in earnings and profits if the interest or gain is effectively connected with the conduct by you of a U.S. trade or business.

Information Reporting and Backup Withholding

Payments to you of interest on a note, and amounts withheld from such payments, if any, generally will be required to be reported to the IRS and to you. Copies of the information returns reporting such interest payments and withholding may also be made available to the tax authorities of the country in which you reside or are established under the provisions of a specific treaty or agreement.

Backup withholding generally will not apply to payments to you of interest on a note if the certification described in “— Tax Consequences to Non-U.S. Holders — Interest on the Notes” is duly provided or you otherwise establish an exemption.

Proceeds from the disposition of a note effected by the U.S. office of a U.S. or foreign broker will be subject to information reporting requirements and backup withholding unless you properly certify under penalties of perjury as to your foreign status on IRS Form W-8BEN or IRS Form W-8BEN-E (or other applicable or

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successor form) and certain other conditions are met or you otherwise establish an exemption. Information reporting requirements and backup withholding generally will not apply to any proceeds from the disposition of a note effected outside the United States by a foreign office of a broker. However, unless such a broker has documentary evidence in its records that you are not a United States person and certain other conditions are met, or you otherwise establish an exemption, information reporting will apply to a payment of the proceeds of the disposition of a note effected outside the United States by such a broker if it has certain relationships with the United States.

Backup withholding is not an additional tax. Any amount withheld under the backup withholding rules is allowable as a credit against your U.S. federal income tax liability, if any, and a refund may be obtained from the IRS if the amounts withheld exceed your actual U.S. federal income tax liability and you timely provide the required information or appropriate claim form to the IRS.

Withholding on Payments to Certain Foreign Entities

Sections 1471 through 1474 of the Code and the U.S. Treasury regulations and administrative guidance issued thereunder (referred to as “FATCA”) impose a 30% U.S. federal withholding tax on payments of interest on the notes and on the gross proceeds from the sale or other disposition of the notes (if such sale or other disposition occurs after December 31, 2018), if paid to a “foreign financial institution” or a “non-financial foreign entity” (each as defined in the Code) (including, in some cases, when such foreign financial institution or non-financial foreign entity is acting as an intermediary), unless: (i) in the case of a foreign financial institution, such institution enters into an agreement with the U.S. government to withhold on certain payments, and to collect and provide to the U.S. tax authorities substantial information regarding U.S. account holders of such institution (which includes certain equity and debt holders of such institution, as well as certain account holders that are foreign entities with U.S. owners); (ii) in the case of a non-financial foreign entity, such entity certifies that it does not have any “substantial United States owners” (as defined in the Code) or provides the withholding agent with a certification identifying its direct and indirect substantial United States owners (generally by providing an IRS Form W-8BEN-E); or (iii) the foreign financial institution or non-financial foreign entity otherwise qualifies for an exemption from these rules and provides appropriate documentation (such as an IRS Form W-8BEN-E). Foreign financial institutions located in jurisdictions that have an intergovernmental agreement with the United States with respect to these rules may be subject to different rules. Under certain circumstances, a beneficial owner of notes might be eligible for refunds or credits of such taxes. You should consult your tax advisor regarding the effects of FATCA on your investment in the notes.

THE PRECEDING DISCUSSION OF CERTAIN U.S. FEDERAL INCOME TAX CONSIDERATIONS IS FOR GENERAL INFORMATION ONLY AND IS NOT TAX ADVICE. WE URGE YOU TO CONSULT YOUR OWN TAX ADVISOR REGARDING THE PARTICULAR U.S. FEDERAL, STATE, LOCAL AND FOREIGN TAX CONSEQUENCES OF ACQUIRING, HOLDING AND DISPOSING OF OUR NOTES, INCLUDING THE CONSEQUENCES OF ANY PROPOSED CHANGE IN APPLICABLE LAWS.

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UNDERWRITING

Subject to the terms and conditions in the underwriting agreement dated the date of this prospectus supplement by and among us and the underwriters named below, for whom Wells Fargo Securities, LLC, PNC Capital Markets LLC, RBC Capital Markets, LLC and U.S. Bancorp Investments, Inc. are acting as representatives, we have agreed to sell to each of the underwriters, and each of the underwriters has agreed to purchase from us, severally and not jointly, the principal amount of the notes set forth opposite the underwriter’s name.

The underwriting agreement provides that the obligations of the underwriters to purchase the notes included in this offering are subject to approval of legal matters by counsel and certain other conditions. Under the terms and conditions of the underwriting agreement, if the underwriters purchase any of the notes, then they are obligated to purchase all of the notes.

The underwriters propose to offer the notes initially at the public offering prices on the cover page of this prospectus supplement. After the initial offering of the notes to the public, the public offering prices and other selling terms to dealers may be changed.

We estimate that the total expenses of this offering to be paid by us, excluding the underwriting discount, will be approximately $300,000.

In connection with this offering and in compliance with applicable law, the underwriters may engage in stabilizing and syndicate covering transactions and penalty bids.

These stabilizing transactions, syndicate covering transactions and penalty bids may have the effect of preventing or retarding a decline in the market price of the notes. They may also cause the price of the notes to be higher than it would otherwise be in the absence of these transactions. These transactions may be effected in the over-the-counter market or otherwise. The underwriters are not required to engage in any of these activities and such activities, if commenced, may be discontinued at any time.

Neither we nor any of the underwriters makes any representation or prediction as to the direction or magnitude of any effect that the transactions described above may have on the price of the notes. In addition, neither we nor any of the underwriters makes any representation that the underwriters will engage in such transactions or that such transactions, once commenced, will not be discontinued without notice.

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We and the underwriters are offering to sell the notes, and seeking offers to buy the notes, only in jurisdictions where such offers and sales are permitted.

We and the underwriters have not and will not authorize the making of any offer of the notes through any financial intermediary on our or their behalf, other than offers made by the underwriters with a view to the final placement of the notes as contemplated in this prospectus. Accordingly, no purchaser of the notes, other than the underwriters, is authorized to make any further offer of the notes on behalf of us or the underwriters.

There is no public market for either series of notes. Neither series of notes will be listed on any securities exchange or included in any automated quotation system. The underwriters have advised us that, following completion of the offering of the notes, they intend to make a market in each series of notes, as permitted by applicable law. They are not obligated, however, to make a market in either series of notes, and may discontinue any market-making activities at any time without notice, in their sole discretion. If any of the underwriters ceases to act as a market-maker for either series of notes for any reason, there can be no assurance that another firm or person will make a market in such series of notes. Accordingly, we cannot assure you as to the development or liquidity of any market for either series of notes.

We have agreed to indemnify the underwriters against certain liabilities, including liabilities under the Securities Act, the Exchange Act or other Federal or state statutory law or to contribute to payments that the underwriters may be required to make in respect of any such liabilities.

Relationships with Underwriters

The underwriters and their affiliates are full service financial institutions engaged in various activities, which may include securities trading, commercial and investment banking, financial advisory, investment management, investment research, principal investment, hedging, financing and brokerage activities. Each of the underwriters and their affiliates have performed investment banking, commercial banking and advisory services for and have had lending relationships with us and our affiliates, including Anadarko, from time to time for which they have received customary fees and expenses. Certain of the underwriters and their affiliates may, from time to time in the future, engage in transactions with and perform services for us and our affiliates in the ordinary course of business. In addition, in the ordinary course of their business activities, the underwriters and their affiliates may make or hold a broad array of investments and actively trade debt and equity securities (or related derivative securities) and financial instruments (including bank loans) for their own account and for the accounts of their customers. Such investments and securities activities may involve securities and/or instruments of ours or our affiliates. The underwriters and their affiliates may also make investment recommendations and/or publish or express independent research views in respect of such securities or financial instruments and may hold, or recommend to clients that they acquire, long and/or short positions in such securities and instruments. Affiliates of each of the underwriters are holders of the 2018 notes or lenders under our revolving credit facility and accordingly will receive a substantial portion of the net proceeds from this offering pursuant to the repayment of such indebtedness. Additionally, Wells Fargo Securities, LLC is an affiliate of the trustee, Wells Fargo Bank, National Association.

Notice to Investors

United Kingdom

This prospectus supplement and the accompanying base prospectus have not been approved by an authorized person for the purposes of section 21 of the Financial Services and Markets Act 2000 (“FSMA”) and are, accordingly, only being distributed in the United Kingdom to, and are only directed at (i) investment professionals falling within the description of persons in Article 19(5) of the Financial Services and Markets Act 2000 (Financial Promotion) Order 2005, as amended (the “Financial Promotion Order”); or (ii) high net worth companies and other persons falling within Article 49(2)(a) to (d) of the Financial Promotion Order; or (iii) to any other person to whom they may otherwise lawfully be communicated or made in accordance with the Financial Promotion Order (all such persons together being referred to as “relevant persons”).

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The notes are only available to, and any invitation, offer or agreement to subscribe, purchase or otherwise acquire such notes will be engaged in only with, relevant persons. Any person who is not a relevant person should not act or rely on this document or any of its contents.

An invitation or inducement to engage in investment activity (within the meaning of Section 21 of FSMA) in connection with the issue or sale of any notes which are the subject of the offering contemplated by this prospectus will only be communicated or caused to be communicated in circumstances in which Section 21(1) of FSMA does not apply to us.

European Economic Area

The notes are not intended to be offered, sold or otherwise made available to and should not be offered, sold or otherwise made available to any retail investor in the European Economic Area. For these purposes a retail investor means a person who is one (or more) of:

Consequently, no key information document required by Regulation (EU) No 1286/2014 (as amended, the “PRIIPs Regulation”) for offering or selling the notes or otherwise making them available to retail investors in the European Economic Area has been prepared and therefore offering or selling the notes or otherwise making them available to any retail investor in the European Economic Area may be unlawful under the PRIIPs Regulation.

This prospectus supplement and the accompanying base prospectus have been prepared on the basis that any offer of notes in any Member State of the European Economic Area will be made pursuant to an exemption under the Prospectus Directive from the requirement to publish a prospectus for offers of notes. This prospectus supplement and the accompanying base prospectus are not a prospectus for the purposes of the Prospectus Directive.

Hong Kong

The notes have not been offered and will not be offered or sold in Hong Kong by means of any document other than (i) in circumstances which do not constitute an offer to the public within the meaning of the Companies (Winding Up and Miscellaneous Provisions) Ordinance (Cap. 32, Laws of Hong Kong), (ii) to “professional investors” within the meaning of the Securities and Futures Ordinance (Cap. 571, Laws of Hong Kong) and any rules made thereunder or (iii) in other circumstances which do not result in the document being a “prospectus” within the meaning of the Companies (Winding Up and Miscellaneous Provisions) Ordinance (Cap. 32, Laws of Hong Kong) and no advertisement, invitation or document relating to the notes may be issued or has been or may be in the possession of any person for the purpose of issue (in each case whether in Hong Kong or elsewhere), which is directed at, or the contents of which are likely to be accessed or read by, the public in Hong Kong (except if permitted to do so under the securities laws of Hong Kong) other than with respect to notes which are or are intended to be disposed of only to persons outside Hong Kong or only to “professional investors” within the meaning of the Securities and Futures Ordinance (Cap. 571, Laws of Hong Kong) and any rules made thereunder.

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Japan

The notes have not been and will not be registered under the Financial Instruments and Exchange Law of Japan (Law No. 25 of 1948, as amended) (the “Financial Instruments and Exchange Law”), and the notes have not been offered or sold and will not be offered or sold, directly or indirectly, in Japan or to, or for the benefit of, any resident of Japan (which term as used herein means any person resident in Japan, including any corporation or other entity organized under the laws of Japan), or to others for re-offering or resale, directly or indirectly, in Japan or to a resident of Japan, except pursuant to an exemption from the registration requirements of, and otherwise in compliance with, the Financial Instruments and Exchange Law and any other applicable laws, regulations and guidelines promulgated by the relevant Japanese governmental and regulatory authorities and in effect at the relevant time.

Singapore

This prospectus supplement and the accompanying base prospectus have not been registered as a prospectus with the Monetary Authority of Singapore. Accordingly, this prospectus supplement and the accompanying base prospectus and any other document or material in connection with the offer or sale, or invitation for subscription or purchase, of the notes may not be circulated or distributed, nor may the notes be offered or sold, or be made the subject of an invitation for subscription or purchase, whether directly or indirectly, to persons in Singapore other than (i) to an institutional investor (as defined in Section 4A of the Securities and Futures Act, Chapter 289 of Singapore (the “SFA”)) pursuant to Section 274 of the SFA, (ii) to a relevant person (as defined in Section 275(2) of the SFA) pursuant to Section 275(1) of the SFA or any person pursuant to an offer referred to in Section 275(1A) of the SFA and in accordance with the conditions specified in Section 275 of the SFA or (iii) otherwise pursuant to, and in accordance with the conditions of, any other applicable provision of the SFA.

Where the notes are subscribed or purchased under Section 275 of the SFA by a “relevant person,” which is:

Switzerland

We have not and will not register with the Swiss Financial Market Supervisory Authority (“FINMA”) as a foreign collective investment scheme pursuant to Article 119 of the Federal Act on Collective Investment Scheme of 23 June 2006, as amended (“CISA”), and accordingly the securities being offered pursuant to this prospectus supplement and the accompanying base prospectus have not and will not be approved, and may not be licenseable, with FINMA. Therefore, the notes have not been authorized for distribution by FINMA as a foreign collective investment scheme pursuant to Article 119 CISA and the notes offered hereby may not be offered to

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the public (as this term is defined in Article 3 CISA) in or from Switzerland. The notes may solely be offered to “qualified investors,” as this term is defined in Article 10 CISA, and in the circumstances set out in Article 3 of the Ordinance on Collective Investment Scheme of 22 November 2006, as amended (“CISO”), such that there is no public offer. Investors, however, do not benefit from protection under CISA or CISO or supervision by FINMA. This prospectus supplement and the accompanying base prospectus and any other materials relating to the notes are strictly personal and confidential to each offeree and do not constitute an offer to any other person. This prospectus supplement and the accompanying base prospectus may only be used by those qualified investors to whom it has been handed out in connection with the offer described herein and may neither directly or indirectly be distributed or made available to any person or entity other than its recipients. It may not be used in connection with any other offer and shall in particular not be copied and/or distributed to the public in Switzerland or from Switzerland. This prospectus supplement and the accompanying base prospectus do not constitute an issue prospectus as that term is understood pursuant to Article 652a and/or 1156 of the Swiss Federal Code of Obligations. We have not applied for a listing of the securities on the SIX Swiss Exchange or any other regulated securities market in Switzerland, and consequently, the information presented in this prospectus supplement and the accompanying base prospectus does not necessarily comply with the information standards set out in the listing rules of the SIX Swiss Exchange and corresponding prospectus schemes annexed to the listing rules of the SIX Swiss Exchange.

Taiwan

The notes have not been and will not be registered with the Financial Supervisory Commission of Taiwan, the Republic of China (“Taiwan”), pursuant to relevant securities laws and regulations and may not be offered or sold in Taiwan through a public offering or in any manner which would constitute an offer within the meaning of the Securities and Exchange Act of Taiwan or would otherwise require registration with or the approval of the Financial Supervisory Commission of Taiwan. No person or entity in Taiwan has been authorized to offer, sell, give advice regarding or otherwise intermediate the offering or sale of the notes in Taiwan.

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LEGAL MATTERS

The validity of the notes offered hereby will be passed upon for us by Vinson & Elkins L.L.P., Houston, Texas. Certain legal matters in connection with the notes offered hereby will be passed upon for the underwriters by Latham  & Watkins LLP, Houston, Texas.

EXPERTS

The consolidated financial statements of Western Gas Partners, LP and subsidiaries as of December 31, 2017 and 2016 and for each of the years in the three-year period ended December 31, 2017, and management’s assessment of the effectiveness of internal control over financial reporting as of December 31, 2017 have been incorporated by reference herein in reliance upon the reports of KPMG LLP, independent registered public accounting firm, incorporated by reference herein, and upon the authority of said firm as experts in accounting and auditing.

FORWARD-LOOKING STATEMENTS

We have made in this prospectus supplement and in the reports and documents incorporated by reference herein, and may from time to time make in other public filings, press releases and statements by management, forward-looking statements concerning our operations, economic performance and financial condition. These forward-looking statements include statements preceded by, followed by or that otherwise include the words “believes,” “expects,” “anticipates,” “intends,” “estimates,” “projects,” “target,” “goal,” “plans,” “objective,” “should” or similar expressions or variations on such expressions. These statements discuss future expectations, contain projections of results of operations or financial condition or include other “forward-looking” information. Although we and our general partner believe that the expectations reflected in such forward-looking statements are reasonable, neither we nor our general partner can give any assurance that such expectations will prove to have been correct.

These forward-looking statements involve risks and uncertainties. Important factors that could cause actual results to differ materially from our expectations include, but are not limited to, the following:

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The risk factors and other factors noted throughout or incorporated by reference in this prospectus could cause actual results to differ materially from those contained in any forward-looking statement. Except as required by law, we undertake no obligation to publicly update or revise any forward-looking statements, whether as a result of new information, future events or otherwise.

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INFORMATION INCORPORATED BY REFERENCE

We file annual, quarterly and other reports with and furnish other information to the SEC. You may read and copy any document we file with or furnish to the SEC at the SEC’s public reference room at 100 F Street, NE, Room 1580, Washington, D.C. 20549. Please call the SEC at 1-800-732-0330 for further information on their public reference room. Our SEC filings are also available at the SEC’s website at http://www.sec.gov.

The SEC allows us to “incorporate by reference” the information we have filed with the SEC. This means that we can disclose important information to you without actually including the specific information in this prospectus by referring you to those documents. The information incorporated by reference is an important part of this prospectus. Information that we file later with the SEC will automatically update and may replace information in this prospectus and information previously filed with the SEC. We incorporate by reference the documents listed below and any future filings made with the SEC under Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act (excluding any information furnished rather than filed), after the date of this prospectus supplement and until the termination of this offering:

You may obtain any of the documents incorporated by reference in this prospectus supplement or the accompanying base prospectus from the SEC through the SEC’s website at the address provided above. You may request a copy of any document incorporated by reference into this prospectus (including exhibits to those documents specifically incorporated by reference in this prospectus supplement), at no cost, by visiting our website at http://www.westerngas.com, or by writing or calling us at the following address:

Investor Relations

Western Gas Partners, LP

1201 Lake Robbins Drive

The Woodlands, Texas 77380-1046

Telephone: (832) 636-6000

The information contained on our website is not part of this prospectus supplement or the accompanying base prospectus.

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PROSPECTUS

WESTERN GAS PARTNERS, LP

Common Units

Preferred Units

Debt Securities

We may offer, from time to time, in one or more series:

The securities we may offer:

Our common units are traded on the New York Stock Exchange under the trading symbol “WES.” We will provide information in the prospectus supplement for the trading market, if any, for any preferred units or debt securities we may offer.

This prospectus provides you with a general description of the securities we may offer. Each time we offer to sell securities we will provide a prospectus supplement that will contain specific information about those securities and the terms of that offering, including the specific manner in which we will offer the securities. The prospectus supplement also may add to, update or change information contained in this prospectus. This prospectus may be used to offer and sell securities only if accompanied by a prospectus supplement. We urge you to read carefully this prospectus and any prospectus supplement before you invest. You should also read the documents we refer to in the “Where You Can Find More Information” section of this prospectus for information on us and our financial statements.

Our principal executive offices are located at 1201 Lake Robbins Drive, The Woodlands, Texas 77380. Our telephone number is (832) 636-6000.

Investing in our securities involves risks. You should carefully consider each of the factors described under “ Risk Factors ,” which begin on page 3 of this prospectus, before you make an investment in our securities.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or passed upon the adequacy or accuracy of this prospectus. Any representation to the contrary is a criminal offense.

The date of this prospectus is November 4, 2016

TABLE OF CONTENTS

You should rely only on the information contained in or incorporated by reference into this prospectus and any prospectus supplement. We have not authorized anyone to provide you with different information. If anyone provides you with different or inconsistent information, you should not rely on it. This prospectus and any prospectus supplement are not an offer to sell, nor a solicitation of an offer to buy, these securities in any jurisdiction where the offer or sale is not permitted. You should not assume that the information incorporated by reference or provided in this prospectus or any prospectus supplement is accurate as of any date other than the date on the front of each such document, regardless of the time of delivery of this prospectus or any sale of a security. Our business, financial condition, results of operations and prospects may have changed since that date.

ABOUT THIS PROSPECTUS

This prospectus, including any information incorporated by reference herein, is part of a registration statement on Form S-3 that we have filed with the Securities and Exchange Commission, or the SEC, using a “shelf” registration process. Under this shelf registration process, we may, from time to time, offer and sell our common units, preferred units or debt securities described in this prospectus in one or more offerings. This prospectus provides you with a general description of us and the securities offered under this prospectus.

Each time we sell securities with this prospectus, we will provide you with this prospectus and a prospectus supplement containing specific information about the terms of that offering and the securities being offered. The prospectus supplement may also add to, update or change information in this prospectus. You should read this prospectus and any prospectus supplement carefully before you invest. If there is any inconsistency between the information in this prospectus and any prospectus supplement, the information in the prospectus supplement will control.

This prospectus contains summaries of certain provisions contained in some of the documents described herein, but reference is made to the actual documents for complete information. All of the summaries are qualified in their entirety by reference to the actual documents. Copies of some of the documents referred to herein have been filed or will be filed or incorporated by reference as exhibits to the registration statement of which this prospectus is a part, and you may obtain copies of those documents as described under the heading “Where You Can Find More Information.”

i

Unless the context otherwise requires, in this prospectus “Western Gas Partners,” “we,” “us,” “our” and like terms refer to Western Gas Partners, LP and its consolidated subsidiaries. “Anadarko” refers to Anadarko Petroleum Corporation and its consolidated subsidiaries, excluding Western Gas Partners. “WGP” refers to Western Gas Equity Partners, LP and its consolidated subsidiaries, excluding Western Gas Holdings, LLC and Western Gas Partners.

ii

ABOUT WESTERN GAS PARTNERS, LP

We are a growth-oriented Delaware master limited partnership formed by Anadarko to acquire, own, develop and operate midstream energy assets.

CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS

We have made in this prospectus and in the reports and documents incorporated by reference herein, and may from time to time make in other public filings, press releases and statements by management, forward-looking statements concerning our operations, economic performance and financial condition. These forward-looking statements include statements preceded by, followed by or that otherwise include the words “believes,” “expects,” “anticipates,” “intends,” “estimates,” “projects,” “target,” “goal,” “plans,” “objective,” “should” or similar expressions or variations of such expressions. These statements discuss future expectations, contain projections of results of operations or financial condition or include other “forward-looking” information.

Although we and our general partner believe that the expectations reflected in such forward-looking statements are reasonable, neither we nor our general partner can give any assurance that such expectations will prove to have been correct. These forward-looking statements involve risks and uncertainties. Important factors that could cause actual results to differ materially from our expectations include, but are not limited to, the following:

1

The risk factors and other factors noted throughout or incorporated by reference in this prospectus could cause our actual results to differ materially from those contained in any forward-looking statement. Except as required by law, we undertake no obligation to publicly update or revise any forward-looking statements, whether as a result of new information, future events or otherwise.

2

RISK FACTORS

An investment in our securities involves a high degree of risk. Specifically, limited partner interests are inherently different from the capital stock of a corporation, although many of the business risks to which we are subject are similar to those that would be faced by a corporation engaged in a similar business. Before you invest in our securities, you should carefully consider the risk factors included in our most recent Annual Report on Form 10-K, Quarterly Reports on Form 10-Q and Current Reports on Form 8-K that are incorporated herein by reference and those that may be described in the applicable prospectus supplement, together with all of the other information included in this prospectus, any prospectus supplement and the documents we incorporate by reference herein or therein.

If any of the risks discussed in the foregoing documents were to occur, our business, financial condition, results of operations or cash flow could be materially adversely affected. In that case, our ability to make distributions to our unitholders or pay interest on, or the principal of, any debt securities, may be reduced, the trading price of our securities could decline and you could lose all or part of your investment.

3

USE OF PROCEEDS

Unless we specify otherwise in any prospectus supplement, we will use the net proceeds we receive from the sale of securities covered by this prospectus for general partnership purposes, which may include, among other things:

The actual application of proceeds from the sale of any particular offering of securities using this prospectus will be described in the applicable prospectus supplement relating to such offering. The precise amount and timing of the application of these proceeds will depend upon our funding requirements and the availability and cost of other funds.

4

RATIO OF EARNINGS TO FIXED CHARGES AND RATIO OF EARNINGS TO COMBINED FIXED CHARGES AND PREFERRED UNIT DISTRIBUTIONS

The following table sets forth our historical consolidated ratio of earnings to fixed charges and ratio of earnings to combined fixed charges and preferred unit distributions for the periods indicated.

DESCRIPTION OF COMMON UNITS

Please see our registration statement on Form 8-A (File No. 001-34046) filed on May 6, 2008 (together with any amendments thereto and the other documents incorporated by reference therein), which is incorporated by reference herein, for a description of our common units, our cash distribution policy and our partnership agreement.

5

DESCRIPTION OF PREFERRED UNITS

Subject to certain approval rights of holders of our Series A Preferred units, our partnership agreement authorizes us to issue an unlimited number of additional limited partner interests and other equity securities on the terms and conditions established by our general partner without the approval of any of our limited partners. In accordance with Delaware law and the provisions of our partnership agreement, and subject to such approval rights, we may issue additional partnership interests that have special voting rights to which our common units are not entitled. As of the date of this prospectus, we have 21,922,831 Series A Preferred units outstanding and no other preferred units outstanding.

Should we offer preferred units under this prospectus, a prospectus supplement relating to the particular series of preferred units offered will include the specific terms of those preferred units, including, among other things, the following:

6

DESCRIPTION OF DEBT SECURITIES

We will issue either senior debt securities or subordinated debt securities under this prospectus, in each case in one or more separate series of debt securities. If we offer a series of senior debt securities, we will issue that series under a senior base indenture, dated as of May 18, 2011, among us, our former subsidiary guarantors and Wells Fargo Bank, National Association, as trustee, as supplemented by a supplemental indenture that we will enter into with the trustee to establish the form and terms of that series of senior debt securities. If we offer a series of subordinated debt securities, we will issue that series under a subordinated base indenture that we will enter into with Wells Fargo Bank, National Association, as trustee, as supplemented by a supplemental indenture that we will also enter into with the trustee to establish the form and terms of that series of subordinated debt securities. References in this prospectus to an “Indenture” are to the particular base indenture under which we may issue a series of debt securities, in each case as supplemented by a supplemental indenture that establishes the form and terms of that series of debt securities. Any series of debt securities that we may issue will be governed by the provisions of the related Indenture and those made part of that Indenture by reference to the Trust Indenture Act of 1939.

This description is a summary of the material provisions of the debt securities and the Indentures. We urge you to read the Indenture applicable to any series of debt securities that we may offer under this prospectus, because that Indenture, and not this description, will govern your rights as a holder of that series. The senior base indenture and a form of the subordinated base indenture are filed as exhibits to the registration statement of which this prospectus is a part. When we offer and sell any particular series of our debt securities under this prospectus, we will file the supplemental indenture establishing the form and terms of that series as an exhibit to a Current Report on Form 8-K.

General

Any series of debt securities:

The Indenture will not limit the total amount of debt securities that may be issued. Debt securities of any series, however, will be issued only up to the aggregate amount authorized for such series and set forth in the prospectus supplement pertaining to that series.

We will prepare a prospectus supplement and an indenture supplement relating to any series of debt securities that we offer, which will include specific terms relating to some or all of the following:

7

This description of debt securities will be deemed modified, amended or supplemented by any description of any series of debt securities set forth in a prospectus supplement related to that series.

The prospectus supplement will also describe any material United States federal income tax consequences or other special considerations regarding the applicable series of debt securities, including those relating to:

Interest payments on debt securities in certificated form may be made by check mailed to the registered holders or, if so stated in the applicable prospectus supplement, at the option of a holder, by wire transfer to an account designated by the holder.

Unless otherwise provided in the applicable prospectus supplement, debt securities may be transferred or exchanged at the office of the Trustee at which its corporate trust business is principally administered in the United States, subject to the limitations provided in the Indenture, without the payment of any service charge, other than any applicable tax or other governmental charge.

Any funds paid to the Trustee or any paying agent for the payment of amounts due on any debt securities that remain unclaimed for two years will be returned to us, and the holders of the debt securities must look only to us for payment after that time.

Certain Covenants

The covenants set forth in the Indenture include the following:

Payment of Principal, any Premium, Interest or Additional Amounts . We will duly and punctually pay the principal of, and premium and interest on or any additional amounts payable with respect to, any debt securities of any series in accordance with their terms and the terms of the Indenture.

Maintenance of Office or Agency . We will maintain an office or agency in each place of payment for each series of debt securities for notice and demand purposes and for the purposes of presenting or surrendering debt securities for payment, registration of transfer or exchange.

Additional Covenants . Any additional covenants with respect to any series of debt securities will be set forth in the supplemental indenture or board resolution and officer’s certificate and prospectus supplement relating thereto.

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Events of Default, Remedies and Notice

Events of Default

Unless otherwise specified in a supplement to the Indenture, each of the following events will be an “Event of Default” under the Indenture with respect to a series of debt securities:

Exercise of Remedies

If an Event of Default, other than an Event of Default described in the fifth bullet point above, occurs and is continuing with respect to a series of debt securities, the Trustee or the holders of at least 25% in principal amount of the outstanding debt securities of that series may declare the entire principal of, premium, if any, and accrued and unpaid interest, if any, on all the debt securities of that series to be due and payable immediately. If an Event of Default described in the fifth bullet point above occurs, the principal of, premium, if any, and accrued and unpaid interest on all outstanding debt securities of all series will become immediately due and payable without any declaration of acceleration or other act on the part of the Trustee or any holders.

A default under the fourth bullet point above will not constitute an Event of Default until the Trustee or the holders of 25% in principal amount of the outstanding debt securities of that series notifies us of the default and such default is not cured within 60 days after receipt of notice.

The holders of a majority in principal amount of the outstanding debt securities of a series may rescind any declaration of acceleration by the Trustee or the holders with respect to the debt securities of that series, but only if:

If an Event of Default occurs and is continuing with respect to a series of debt securities, the Trustee will be under no obligation, except as otherwise provided in the Indenture, to exercise any of the rights or powers under the Indenture at the request or direction of any of the holders of the debt securities of that series, unless such holders have offered to the Trustee reasonable indemnity or security against any costs, liability or expense. No holder may pursue any remedy with respect to the Indenture or the debt securities of any series, except to enforce the right to receive payment of principal, premium or interest on its own debt securities when due, unless:

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The holders of a majority in principal amount of the outstanding debt securities of a series have the right, subject to certain restrictions, to direct the time, method and place of conducting any proceeding for any remedy available to the Trustee or of exercising any right or power conferred on the Trustee with respect to that series of debt securities. The Trustee, however, may refuse to follow any direction that:

Notice of Event of Default

Within 30 days after the occurrence of an Event of Default, we are required to give written notice to the Trustee and indicate the status of the default and what action we are taking or propose to take to cure the default. In addition, we are required to deliver to the Trustee, within 120 days after the end of each fiscal year, a compliance certificate indicating that we have complied with all covenants contained in the Indenture or whether any default or Event of Default has occurred during the previous year.

Within 90 days after the occurrence of any default known to it, the Trustee must mail to each holder of debt securities of the affected series a notice of the default. Except in the case of a default in the payment of principal, premium or interest with respect to any series of debt securities, the Trustee may withhold such notice, but only if and so long as the board of directors, the executive committee or a committee of directors or responsible officers of the Trustee in good faith determines that withholding such notice is in the interests of the holders.

Amendments and Waivers

We may supplement or amend the Indenture without the consent of any holder of debt securities to, among other things:

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In addition, we may amend the Indenture if the holders of a majority in principal amount of all debt securities of each series that would be affected then outstanding under the Indenture consent to it. We may not, however, without the consent of each holder of outstanding debt securities of each series that would be affected, amend the Indenture to:

It shall not be necessary for the consent of the holders under the Indenture to approve the particular form of any proposed amendment. It is sufficient if such consent approves the substance of the proposed amendment. After an amendment under the Indenture requiring the consent of the holders becomes effective, we are required to mail to all holders a notice briefly describing the amendment. The failure to give, or any defect in, such notice, however, will not impair or affect the validity of the amendment.

The holders of a majority in aggregate principal amount of the outstanding debt securities of each affected series, on behalf of all such holders, and subject to certain rights of the Trustee, may waive:

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Satisfaction and Discharge

The Indenture will be discharged and will cease to be of further effect as to all outstanding debt securities of any series issued thereunder, when:

Notwithstanding such satisfaction and discharge, our obligations to compensate and indemnify the Trustee, to pay additional amounts, if any, in respect of debt securities in certain circumstances and to transfer or exchange debt securities pursuant to the terms thereof and our obligations and the obligations of the Trustee to hold funds in trust and to apply such funds pursuant to the terms of the Indenture, with respect to issuing temporary debt securities, with respect to the registration, transfer and exchange of debt securities, with respect to the replacement of mutilated, destroyed, lost or stolen debt securities and with respect to the maintenance of an office or agency for payment, shall in each case survive such satisfaction and discharge.

Defeasance

At any time, we may terminate, with respect to debt securities of a particular series, all our obligations under such series of debt securities and the Indenture, which we call a “legal defeasance.” If we decide to make a legal defeasance, however, we may not terminate our obligations specified in the Indenture, including those:

At any time we may also effect a “covenant defeasance,” which means we have elected to terminate our obligations under the additional covenants established pursuant to the terms of a particular series of debt securities, which covenants are not described in the prospectus but will be described in the prospectus supplement applicable to such series, and any Event of Default resulting from a failure to observe such covenants.

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The legal defeasance option may be exercised notwithstanding a prior exercise of the covenant defeasance option. If the legal defeasance option is exercised, payment of the affected series of debt securities may not be accelerated because of an Event of Default with respect to that series. If the covenant defeasance option is exercised, payment of the affected series of debt securities may not be accelerated because of an Event of Default with respect to the breach of certain agreements specified in the fourth bullet point under “- Events of Default, Remedies and Notice - Events of Default” above or an Event of Default that is added specifically for such series and described in a prospectus supplement.

In order to exercise either defeasance option, we must:

No Personal Liability

Our partners (other than our general partner) and any directors, officers, employees, incorporators, shareholders, partners and members of our general partner will not be liable for:

By accepting a debt security, each holder will be deemed to have waived and released all such liability. This waiver and release are part of the consideration for the issuance of the debt securities. This waiver may not be effective, however, to waive liabilities under the Federal securities laws and it is the view of the SEC that such a waiver is against public policy.

No Protection in the Event of a Change of Control

Unless otherwise set forth in the prospectus supplement, the debt securities will not contain any provisions that protects the holders of the debt securities in the event of our change of control or in the event of a highly leveraged transaction, whether or not such transaction results in our change of control.

Provisions Relating only to the Senior Debt Securities

The senior debt securities will rank equally in right of payment with all of our other unsubordinated debt. The senior debt securities will be effectively subordinated, however, to all of our secured debt to the extent of the value of the collateral securing such debt. We will disclose the amount of our secured debt in the prospectus supplement.

Provisions Relating only to the Subordinated Debt Securities

Subordinated Debt Securities Subordinated to Senior Indebtedness

The subordinated debt securities will rank junior in right of payment to all of our Senior Indebtedness. “Senior Indebtedness” will be defined in a supplemental indenture respecting any issuance of a series of subordinated debt securities, and the definition will be set forth in the prospectus supplement.

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Payment Blockages

The Indenture respecting any series of subordinated debt securities will provide that no payment of principal, interest and any premium on the subordinated debt securities may be made in the event:

No Limitation on Amount of Senior Debt

The Indenture respecting any series of subordinated debt securities will not limit the amount of Senior Indebtedness that we may incur, unless otherwise indicated in the prospectus supplement.

Book Entry, Delivery and Form

The debt securities of a particular series may be issued in whole or in part in the form of one or more global certificates that will be deposited with the Trustee as custodian for The Depository Trust Company, New York, New York (“DTC”). This means that we will not issue certificates to each holder except in the limited circumstances described below. Instead, one or more global debt securities will be issued to DTC, who will keep a computerized record of its participants (for example, your broker) whose clients have purchased the debt securities. The participant will then keep a record of its clients who purchased the debt securities. Unless it is exchanged in whole or in part for a certificated debt security, a global debt security may not be transferred, except that DTC, its nominees and their successors may transfer a global debt security as a whole to one another.

Beneficial interests in global debt securities will be shown on, and transfers of global debt securities will be made only through, records maintained by DTC and its participants.

DTC has provided us the following information: DTC is a limited-purpose trust company organized under the New York Banking Law, a “banking organization” within the meaning of the New York Banking Law, a member of the United States Federal Reserve System, a “clearing corporation” within the meaning of the New York Uniform Commercial Code and a “clearing agency” registered under the provisions of Section 17A of the Securities Exchange Act of 1934, as amended (the “Exchange Act”). DTC holds securities that its participants (“Direct Participants”) deposit with DTC. DTC also records the settlement among Direct Participants of securities transactions, such as transfers and pledges, in deposited securities through computerized records for Direct Participants’ accounts. This eliminates the need to exchange certificates. Direct Participants include securities brokers and dealers, banks, trust companies, clearing corporations and certain other organizations.

DTC’s book-entry system is also used by other organizations such as securities brokers and dealers, banks and trust companies that work through a Direct Participant. The rules that apply to DTC and its participants are on file with the SEC.

DTC is owned by a number of its participants and by the New York Stock Exchange, Inc., the NYSE Alternext US LLC (formerly the American Stock Exchange, Inc.) and the Financial Industry Regulatory Authority, Inc. (“FINRA”).

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We will wire all payments on the global debt securities to DTC’s nominee. We and the Trustee will treat DTC’s nominee as the owner of the global debt securities for all purposes. Accordingly, we, the Trustee and any paying agent will have no direct responsibility or liability to pay amounts due on the global debt securities to owners of beneficial interests in the global debt securities.

It is DTC’s current practice, upon receipt of any payment on the global debt securities, to credit Direct Participants’ accounts on the payment date according to their respective holdings of beneficial interests in the global debt securities as shown on DTC’s records. In addition, it is DTC’s current practice to assign any consenting or voting rights to Direct Participants whose accounts are credited with debt securities on a record date, by using an omnibus proxy. Payments by participants to owners of beneficial interests in the global debt securities, and voting by participants, will be governed by the customary practices between the participants and owners of beneficial interests, as is the case with debt securities held for the account of customers registered in “street name.” However, payments will be the responsibility of the participants and not of DTC, the Trustee or us.

Debt securities represented by a global debt security will be exchangeable for certificated debt securities with the same terms in authorized denominations only if:

Governing Law

Each Indenture and all of the debt securities will be governed by the laws of the State of New York.

The Trustee

Unless we otherwise specify in the applicable prospectus supplement, the Trustee for each series of debt securities will be Wells Fargo Bank, National Association. We may maintain a banking relationship in the ordinary course of business with our Trustee and one or more of its affiliates.

Resignation or Removal of Trustee

If the Trustee has or acquires a conflicting interest within the meaning of the Trust Indenture Act of 1939 after a default has occurred and is continuing, the Trustee must either eliminate its conflicting interest within 90 days, apply to the SEC for permission to continue as Trustee or resign, to the extent and in the manner provided by, and subject to the provisions of, the Trust Indenture Act and the applicable Indenture. Any resignation will require the appointment of a successor trustee under the applicable Indenture in accordance with the terms and conditions of such Indenture.

The Trustee may resign or be removed by us with respect to one or more series of debt securities and a successor Trustee may be appointed to act with respect to any such series. The holders of a majority in aggregate principal amount of the debt securities of any series may remove the Trustee with respect to the debt securities of such series.

Limitations on Trustee if it is Our Creditor

Each Indenture will contain certain limitations on the right of the Trustee, in the event that it becomes a creditor of us, to obtain payment of claims in certain cases, or to realize on certain property received in respect of any such claim as security or otherwise.

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Annual Trustee Report to Holders of Debt Securities

The Trustee is required to submit an annual report to the holders of the debt securities regarding, among other things, the Trustee’s eligibility to serve as such, the priority of the Trustee’s claims regarding certain advances made by it, and any action taken by the Trustee materially affecting the debt securities.

Certificates and Opinions to be Furnished to Trustee

Each Indenture will provide that, in addition to other certificates or opinions that may be specifically required by other provisions of the Indenture, every application by us for action by the Trustee shall be accompanied by a certificate of certain of our officers and an opinion of counsel (who may be our counsel) stating that, in the opinion of the signers, all conditions precedent to such action have been complied with by us.

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MATERIAL U.S. FEDERAL INCOME TAX CONSEQUENCES

This section summarizes the material U.S. federal income tax consequences that may be relevant to prospective common unitholders and is based upon current provisions of the U.S. Internal Revenue Code of 1986, as amended (the “Code”), existing and proposed U.S. Treasury regulations thereunder (the “Treasury Regulations”), and current administrative rulings and court decisions, all of which are subject to change. Changes in these authorities may cause the federal income tax consequences to a prospective common unitholder to vary substantially from those described below, possibly on a retroactive basis. Unless the context otherwise requires, references in this section to “we” or “us” are references to Western Gas Partners, LP.

Legal conclusions contained in this section, unless otherwise noted, are the opinion of Vinson & Elkins L.L.P. insofar as they related to matters of U.S. federal income tax law and are based on the accuracy of representations made by us to them for this purpose. However, this section does not address all federal income tax matters that affect us or our common unitholders and does not describe the application of the alternative minimum tax that may be applicable to certain unitholders. Furthermore, this section focuses on common unitholders who are individual citizens or residents of the United States (for federal income tax purposes), who have the U.S. dollar as their functional currency, who use the calendar year as their taxable year, and who hold common units as capital assets (generally, property that is held for investment). This section has limited applicability to corporations, partnerships (including entities treated as partnerships for federal income tax purposes), estates, trusts, non-resident aliens or other common unitholders subject to specialized tax treatment, such as tax-exempt institutions, non-U.S. persons, individual retirement accounts (“IRAs”), employee benefit plans, real estate investment trusts or mutual funds. Accordingly, we encourage each common unitholder to consult the unitholder’s own tax advisor in analyzing the federal, state, local and non-U.S. tax consequences particular to that unitholder resulting from ownership or disposition of its units and potential changes in applicable tax laws.

No ruling has been or will be requested from the IRS regarding any matter affecting us. Instead, we are relying on opinions and advice of Vinson & Elkins L.L.P. with respect to the matters described herein. An opinion of counsel represents only that counsel’s best legal judgment and does not bind the Internal Revenue Service (“IRS”) or a court. Accordingly, the opinions and statements made herein may not be sustained by a court if contested by the IRS. Any such contest of the matters described herein may materially and adversely impact the market for our units and the prices at which such units trade. In addition, our costs of any contest with the IRS will be borne indirectly by our common unitholders because the costs will reduce our cash available for distribution. Furthermore, the tax consequences of an investment in us may be significantly modified by future legislative or administrative changes or court decisions, which may be retroactively applied.

For the reasons described below, Vinson & Elkins L.L.P. has not rendered an opinion with respect to the following federal income tax issues: (1) the treatment of a common unitholder whose units are the subject of a securities loan (e.g., a loan to a short seller to cover a short sale of units) (please read “—Tax Consequences of Unit Ownership-Treatment of Securities Loans”); (2) whether our monthly convention for allocating taxable income and losses is permitted by existing Treasury Regulations (please read “—Disposition of Units-Allocations Between Transferors and Transferees”); and (3) whether our method for taking into account Section 743 adjustments is sustainable in certain cases (please read “—Tax Consequences of Unit Ownership-Section 754 Election” and “—Uniformity of Units”).

Taxation of the Partnership

Partnership Status

We expect to be treated as a partnership for U.S. federal income tax purposes and, therefore, generally will not be liable for entity-level federal income taxes. Instead, as described below, each of our common unitholders will take into account its respective share of our items of income, gain, loss and deduction in computing its federal income tax liability as if the common unitholder had earned such income directly, even if we make no cash distributions to the common unitholder.

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Section 7704 of the Code generally provides that publicly traded partnerships will be treated as corporations for federal income tax purposes. However, if 90% or more of a partnership’s gross income for every taxable year it is publicly traded consists of “qualifying income,” the partnership may continue to be treated as a partnership for federal income tax purposes (the “Qualifying Income Exception”). Qualifying income includes income and gains derived from the exploration, development, mining or production, processing, refining, transportation, storage, and marketing of certain natural resources, including crude oil, natural gas and products thereof (including NGLs), as well as other types of income, such as interest (other than from a financial business), dividends, gains from the sale of real property, and gains from the sale or other disposition of capital assets held for the production of income that otherwise constitutes qualifying income. We estimate that less than 2% of our current gross income is not qualifying income; however, this estimate could change from time to time.

Based upon factual representations made by us and our general partner, Vinson & Elkins L.L.P. is of the opinion that we will be treated as a partnership for federal income tax purposes, and each of our partnership or limited liability company subsidiaries will be treated as a partnership or will be disregarded as an entity separate from us for federal income tax purposes. The representations made by us and our general partner upon which Vinson & Elkins L.L.P. has relied in rendering its opinion include, without limitation:

We believe that these representations are true and will be true in the future.

If we fail to meet the Qualifying Income Exception, other than a failure that is determined by the IRS to be inadvertent and that is cured within a reasonable time after discovery (in which case the IRS may also require us to make adjustments with respect to our common unitholders or pay other amounts), we will be treated as transferring all of our assets, subject to liabilities, to a newly formed corporation, on the first day of the year in which we fail to meet the Qualifying Income Exception, in return for stock in that corporation and then as distributing that stock to our common unitholders in liquidation. This deemed contribution and liquidation should not result in the recognition of taxable income by our common unitholders or us so long as our liabilities do not exceed the tax basis of our assets. Thereafter, we would be treated as an association taxable as a corporation for federal income tax purposes.

The present federal income tax treatment of publicly traded partnerships, including us, or an investment in our common units may be modified by administrative or legislative action or judicial interpretation at any time. For example, from time to time, members of the U.S. Congress propose and consider substantive changes to the existing federal income tax laws that affect publicly traded partnerships. One such legislative proposal would have eliminated the Qualifying Income Exception upon which we rely for our treatment as a partnership for U.S. federal income tax purposes.

In addition, the IRS has issued proposed regulations regarding qualifying income under Section 7704(d)(1)(E) of the Code (the “Proposed Regulations”). We do not believe the Proposed Regulations affect our ability to qualify as a publicly traded partnership. However, there are no assurances that final regulations will not include changes that interpret Section 7704(d)(10(E) in a manner that is contrary to the proposed Regulations, which could modify the amount of our gross income that we are able to treat as qualifying income for the purposes of the Qualifying Income Exception. We are unable to predict whether any such changes

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will ultimately be enacted. However, it is possible that a change in law could affect us and may be applied retroactively. Any such changes could negatively impact the value of an investment in our units.

If for any reason we are taxable as a corporation in any taxable year, our items of income, gain, loss and deduction would be taken into account by us in determining the amount of our liability for federal income tax, rather than being passed through to our common unitholders. Our taxation as a corporation would materially reduce the cash available for distribution to unitholders and thus would likely substantially reduce the value of our units. Any distribution made to a unitholder at a time we are treated as a corporation would be (i) a taxable dividend to the extent of our current or accumulated earnings and profits, then (ii) a nontaxable return of capital to the extent of the unitholder’s tax basis in its units, and thereafter (iii) taxable capital gain.

The remainder of this discussion is based on the opinion of Vinson & Elkins L.L.P. that we will be treated as a partnership for federal income tax purposes.

Tax Consequences of Unit Ownership

Limited Partner Status

Common unitholders who are admitted as limited partners of the partnership as well as common unitholders whose units are held in street name or by a nominee and who have the right to direct the nominee in the exercise of all substantive rights attendant to the ownership of units, will be treated as partners of the partnership for federal income tax purposes. For a discussion related to the risks of losing partner status as a result of securities loans, please read “—Treatment of Securities Loans.” Unitholders who are not treated as partners of the partnership as described above are urged to consult their own tax advisors with respect to the tax consequences applicable to them under their particular circumstances.

Flow-Through of Taxable Income

Subject to the discussion below under “—Entity-Level Collections of Unitholder Taxes” with respect to payments we may be required to make on behalf of our common unitholders, we will not pay any federal income tax. Rather, each common unitholder will be required to report on its federal income tax return each year its share of our income, gains, losses and deductions for our taxable year or years ending with or within its taxable year. Consequently, we may allocate income to a common unitholder even if that unitholder has not received a cash distribution.

Basis of Units

A common unitholder’s tax basis in its units initially will be the amount paid for those units increased by the unitholder’s initial allocable share of our “nonrecourse liabilities” (liabilities for which no partner bears the economic risk of loss). That basis generally will be (i) increased by the unitholder’s share of our income and any increases in such unitholder’s share of our nonrecourse liabilities, and (ii) decreased, but not below zero, by the amount of all distributions to the unitholder, the unitholder’s share of our losses, and any decreases in the unitholder’s share of our nonrecourse liabilities and its share of our expenditures that are neither deductible nor required to be capitalized. The IRS has ruled that a partner who acquires interests in a partnership in separate transactions must combine those interests and maintain a single adjusted tax basis for all of those interests.

Treatment of Distributions

Distributions by us to a common unitholder generally will not be taxable to the common unitholder, unless such distributions exceed the unitholder’s tax basis in its common units, in which case the unitholder generally will recognize gain taxable in the manner described below under “—Disposition of Units.”

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Any reduction in a unitholder’s share of our nonrecourse liabilities will be treated as a distribution by us of cash to that unitholder. A decrease in a unitholder’s percentage interest in us because of our issuance of additional units may decrease the unitholder’s share of our liabilities. For purposes of the foregoing, a unitholder’s share of our nonrecourse liabilities generally will be based upon that unitholder’s share of the unrealized appreciation (or depreciation) in our assets, to the extent thereof, with any excess liabilities allocated based on the unitholder’s share of our profits. Please read “—Disposition of Units.”

A non-pro rata distribution of money or property (including a deemed distribution as a result of the reallocation of our liabilities described above) may cause a unitholder to recognize ordinary income, if the distribution reduces the unitholder’s share of our “unrealized receivables,” including depreciation and depletion recapture and substantially appreciated “inventory items,” both as defined in Section 751 of the Code (“Section 751 Assets”). To the extent of such reduction, the unitholder would be deemed to receive its proportionate share of the Section 751 Assets and exchange such assets with us in return for a portion of the non-pro rata distribution. This deemed exchange generally will result in the unitholder’s recognition of ordinary income in an amount equal to the excess of (1) the non-pro rata portion of that distribution over (2) the unitholder’s tax basis (generally zero) in the Section 751 Assets deemed to be relinquished in the exchange.

Limitations on Deductibility of Losses

A common unitholder may not be entitled to deduct the full amount of loss we allocate to it because its share of our losses will be limited to the lesser of (i) the unitholder’s tax basis in its units, and (ii) in the case of a unitholder that is an individual, estate, trust or certain types of closely-held corporations, the amount for which the unitholder is considered to be “at risk” with respect to our activities. In general, a unitholder will be at risk to the extent of its tax basis in its units, reduced by (1) any portion of that basis attributable to the unitholder’s share of our liabilities, (2) any portion of that basis representing amounts otherwise protected against loss because of a guarantee, stop loss agreement or similar arrangement and (3) any amount of money the unitholder borrows to acquire or hold its units, if the lender of those borrowed funds owns an interest in us, is related to another unitholder or can look only to the units for repayment. A unitholder subject to the at risk limitation must recapture losses deducted in previous years to the extent that distributions (including distributions deemed to result from a reduction in a unitholder’s share of nonrecourse liabilities) cause the unitholder’s at risk amount to be less than zero at the end of any taxable year.

Losses disallowed to a common unitholder or recaptured as a result of the basis or at risk limitations will carry forward and will be allowable as a deduction in a later year to the extent that the unitholder’s tax basis or at risk amount, whichever is the limiting factor, is subsequently increased. Upon a taxable disposition of units, any gain recognized by a unitholder can be offset by losses that were previously suspended by the at risk limitation but not losses suspended by the basis limitation. Any loss previously suspended by the at risk limitation in excess of that gain can no longer be used, and will not be available to offset a unitholder’s salary or active business income.

In addition to the basis and at risk limitations, a passive activity loss limitation generally limits the deductibility of losses incurred by individuals, estates, trusts, some closely-held corporations and personal service corporations from “passive activities” (generally, trade or business activities in which the taxpayer does not materially participate). The passive loss limitations are applied separately with respect to each publicly-traded partnership. Consequently, any passive losses we generate will be available to offset only passive income generated by us. Passive losses that exceed a unitholder’s share of passive income we generate may be deducted in full when the unitholder disposes of all of its units in a fully taxable transaction with an unrelated party. The passive loss rules generally are applied after other applicable limitations on deductions, including the at risk and basis limitations.

The passive loss rules are required to be applied separately with respect to items attributable to each separate publicly traded partnership. The application of this requirement to a WES unitholder who is also a WGP unitholder is uncertain. It is possible that amounts allocated to a WGP unitholder that are attributable to WGP’s

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interest in WES may be combined with amounts allocated directly to a WES unitholder. Alternatively, such amounts may need to be treated as attributable to interests in separate publicly traded partnerships. If you hold interests in both WES and WGP, you should consult your own tax advisor regarding the application of the passive loss rules.

Limitations on Interest Deductions

The deductibility of a non-corporate taxpayer’s “investment interest expense” generally is limited to the amount of that taxpayer’s “net investment income.” Investment interest expense includes:

The computation of a common unitholder’s investment interest expense will take into account interest on any margin account borrowing or other loan incurred to purchase or carry a unit. Net investment income includes gross income from property held for investment and amounts treated as portfolio income under the passive loss rules, less deductible expenses other than interest directly connected with the production of investment income. Net investment income generally does not include qualified dividend income (if applicable) or gains attributable to the disposition of property held for investment. A common unitholder’s share of a publicly traded partnership’s portfolio income and, according to the IRS, net passive income will be treated as investment income for purposes of the investment interest expense limitation.

Entity-Level Collections of Unitholder Taxes

If we are required or elect under applicable law to pay any federal, state, local or non-U.S. tax on behalf of any current or former common unitholder, we are authorized to treat the payment as a distribution of cash to the relevant unitholder. Where the tax is payable on behalf of all unitholders or we cannot determine the specific unitholder on whose behalf the tax is payable, we are authorized to treat the payment as a distribution to all current unitholders. We are authorized to amend our partnership agreement in the manner necessary to maintain uniformity of intrinsic tax characteristics of units and to adjust later distributions, so that after giving effect to these distributions, the priority and characterization of distributions otherwise applicable under our partnership agreement is maintained as nearly as is practicable. Payments by us as described above could give rise to an overpayment of tax on behalf of a common unitholder, in which event the common unitholder may be entitled to claim a refund of the overpayment amount. Common unitholders are urged to consult their tax advisors to determine the consequences to them of any tax payment we make on their behalf.

Allocation of Income, Gain, Loss and Deduction

Our items of income, gain, loss and deduction generally will be allocated among our common unitholders in accordance with their percentage interests in us. At any time that incentive distributions are made to our general partner, gross income will be allocated to the recipients to the extent of these distributions.

Specified items of our income, gain, loss and deduction will be allocated under Section 704(c) of the Code (or the principles of Section 704(c) of the Code) to account for any difference between the tax basis and fair market value of our assets at the time such assets are contributed to us and at the time of any subsequent offering of our units (a “Book-Tax Disparity”). As a result, the federal income tax burden associated with any Book-Tax Disparity immediately prior to an offering generally will be borne by our partners holding interests in us prior to such offering. In addition, items of recapture income will be specially allocated to the extent possible to the unitholder who was allocated the deduction giving rise to that recapture income in order to minimize the recognition of ordinary income by other unitholders.

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An allocation of items of our income, gain, loss or deduction, other than an allocation required by the Code to eliminate a Book-Tax Disparity, will generally be given effect for federal income tax purposes in determining a partner’s share of an item of income, gain, loss or deduction only if the allocation has “substantial economic effect.” In any other case, a partner’s share of an item will be determined on the basis of the partner’s interest in us, which will be determined by taking into account all the facts and circumstances, including (i) the partner’s relative contributions to us, (ii) the interests of all the partners in profits and losses, (iii) the interest of all the partners in cash flow and (iv) the rights of all the partners to distributions of capital upon liquidation. Vinson & Elkins L.L.P. is of the opinion that, with the exception of the issues described in “—Section 754 Election” and “—Disposition of Units-Allocations Between Transferors and Transferees,” allocations of income, gain, loss or deduction under our partnership agreement will be given effect for federal income tax purposes.

Treatment of Securities Loans

A unitholder whose units are loaned (for example, a loan to a “short seller” to cover a short sale of units) may be treated as having disposed of those units. If so, such unitholder would no longer be treated for tax purposes as a partner with respect to those units during the period of the loan and may recognize gain or loss from the disposition. As a result, during this period (i) any of our income, gain, loss or deduction allocated to those units would not be reportable by the lending unitholder and (ii) any cash distributions received by the unitholder as to those units may be treated as ordinary taxable income.

Due to a lack of controlling authority, Vinson & Elkins L.L.P. has not rendered an opinion regarding the tax treatment of a unitholder that enters into a securities loan with respect to its units. Unitholders desiring to assure their status as partners and avoid the risk of income recognition from a loan of their units are urged to consult their own tax advisors and to modify any applicable brokerage account agreements to prohibit their brokers from borrowing and lending their units. The IRS has announced that it is studying issues relating to the tax treatment of short sales of partnership interests. Please read “— Disposition of Units-Recognition of Gain or Loss.”

Tax Rates

Under current law, the highest marginal federal income tax rates for individuals applicable to ordinary income and long-term capital gains (generally, gains from the sale or exchange of certain investment assets held for more than one year) are 39.6% and 20%, respectively. These rates are subject to change by new legislation at any time.

In addition, a 3.8% net investment income tax (“NIIT”) applies to certain net investment income earned by individuals, estates, and trusts. For these purposes, net investment income generally includes a common unitholder’s allocable share of our income and gain realized by a common unitholder from a sale of units. In the case of an individual, the tax will be imposed on the lesser of (i) the common unitholder’s net investment income from all investments, or (ii) the amount by which the common unitholder’s modified adjusted gross income exceeds $250,000 (if the common unitholder is married and filing jointly or a surviving spouse), $125,000 (if married filing separately) or $200,000 (if the unitholder is unmarried or in any other case). In the case of an estate or trust, the tax will be imposed on the lesser of (i) undistributed net investment income, or (ii) the excess adjusted gross income over the dollar amount at which the highest income tax bracket applicable to an estate or trust begins.

Section 754 Election

We have made the election permitted by Section 754 of the Code that permits us to adjust the tax bases in our assets as to specific purchasers of our units under Section 743(b) of the Code. That election is irrevocable without the consent of the IRS. The Section 743(b) adjustment separately applies to each purchaser of common units based upon the values and bases of our assets at the time of the relevant purchase, and the adjustment will reflect the purchase price paid. The Section 743(b) adjustment does not apply to a person who purchases units directly from us.

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Under our partnership agreement, we are authorized to take a position to preserve the uniformity of units even if that position is not consistent with applicable Treasury Regulations. A literal application of Treasury Regulations governing a Section 743(b) adjustment attributable to properties depreciable under Section 167 of the Code may give rise to differences in the taxation of unitholders purchasing units from us and unitholders purchasing from other unitholders. If we have any such properties, we intend to adopt methods employed by other publicly traded partnerships to preserve the uniformity of units, even if inconsistent with existing Treasury Regulations, and Vinson & Elkins L.L.P. has not opined on the validity of this approach. Please read “—Uniformity of Units.”

The IRS may challenge the positions we adopt with respect to depreciating or amortizing the Section 743(b) adjustment we take to preserve the uniformity of units due to lack of controlling authority. Because a unitholder’s tax basis in its units is reduced by its share of our items of deduction or loss, any position we take that understates deductions will overstate a unitholder’s basis in its units and may cause the unitholder to understate gain or overstate loss on any sale of such units. Please read “—Disposition of Units-Recognition of Gain or Loss.” If a challenge to such treatment were sustained, the gain from the sale of units may be increased without the benefit of additional deductions.

The calculations involved in the Section 754 election are complex and will be made on the basis of assumptions as to the value of our assets and other matters. The IRS could seek to reallocate some or all of any Section 743(b) adjustment we have allocated to our assets subject to depreciation to goodwill or nondepreciable assets. Goodwill, as an intangible asset, is generally amortizable over a longer period of time or under a less accelerated method than our tangible assets. We cannot assure any unitholder that the determinations we make will not be successfully challenged by the IRS or that the resulting deductions will not be reduced or disallowed altogether. Should the IRS require a different tax basis adjustment to be made, and should, in our opinion, the expense of compliance exceed the benefit of the election, we may seek permission from the IRS to revoke our Section 754 election. If permission is granted, a subsequent purchaser of units may be allocated more income than it would have been allocated had the election not been revoked.

Tax Treatment of Operations

Accounting Method and Taxable Year

We use the year ending December 31 as our taxable year and the accrual method of accounting for federal income tax purposes. Each common unitholder will be required to include in its tax return its share of our income, gain, loss and deduction for each taxable year ending within or with its taxable year. In addition, a common unitholder who has a taxable year ending on a date other than December 31 and who disposes of all of its units following the close of our taxable year but before the close of its taxable year must include its share of our income, gain, loss and deduction in income for its taxable year, with the result that it will be required to include in income for its taxable year its share of more than twelve months of our income, gain, loss and deduction. Please read “—Disposition of Units-Allocations Between Transferors and Transferees.”

Tax Basis, Depreciation and Amortization

The tax basis of our assets will be used for purposes of computing depreciation and cost recovery deductions and, ultimately, gain or loss on the disposition of those assets. If we dispose of depreciable property by sale, foreclosure or otherwise, all or a portion of any gain, determined by reference to the amount of depreciation and depletion deductions previously taken, may be subject to the recapture rules and taxed as ordinary income rather than capital gain. Similarly, a unitholder who has taken cost recovery or depreciation deductions with respect to property we own will likely be required to recapture some or all of those deductions as ordinary income upon a sale of its interest in us. Please read “—Tax Consequences of Unit Ownership-Allocation of Income, Gain, Loss and Deduction.”

The costs we incur in offering and selling our units (called “syndication expenses”) must be capitalized and cannot be deducted currently, ratably or upon our termination. While there are uncertainties regarding the

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classification of costs as organization expenses, which may be amortized by us, and as syndication expenses, which may not be amortized by us, the underwriting discounts and commissions we incur will be treated as syndication expenses. Please read “Disposition of Units-Recognition of Gain or Loss.”

Valuation and Tax Basis of Our Properties

The federal income tax consequences of the ownership and disposition of units will depend in part on our estimates of the relative fair market values and the tax bases of our assets. Although we may from time to time consult with professional appraisers regarding valuation matters, we will make many of the relative fair market value estimates and tax basis determinations ourselves. These estimates and determinations of tax basis are subject to challenge and will not be binding on the IRS or the courts. If the estimates of fair market value or basis are later found to be incorrect, the character and amount of items of income, gain, loss or deduction previously reported by common unitholders could change, and common unitholders could be required to adjust their tax liability for prior years and incur interest and penalties with respect to those adjustments.

Disposition of Units

Recognition of Gain or Loss

A common unitholder will be required to recognize gain or loss on a sale of units equal to the difference between the unitholder’s amount realized and tax basis in the units sold. A common unitholder’s amount realized generally will equal the sum of the cash and the fair market value of other property it receives plus its share of our liabilities with respect to the units sold. Because the amount realized includes a unitholder’s share of our liabilities, the gain recognized on the sale of units could result in a tax liability in excess of any cash received from the sale.

Except as noted below, gain or loss recognized by a common unitholder on the sale or exchange of a unit held for more than one year generally will be taxable as long-term capital gain or loss. However, gain or loss recognized on the disposition of units will be separately computed and taxed as ordinary income or loss under Section 751 of the Code to the extent attributable to Section 751 Assets, such as depreciation or depletion recapture and our “inventory items,” regardless of whether such inventory item is substantially appreciated in value. Ordinary income attributable to Section 751 Assets may exceed net taxable gain realized on the sale of a unit and may be recognized even if there is a net taxable loss realized on the sale of a unit. Thus, a unitholder may recognize both ordinary income and capital gain or loss upon a sale of units. Net capital loss may offset capital gains and, in the case of individuals, up to $3,000 of ordinary income per year. Both ordinary income and capital gain recognized may be subject to the NIIT in certain circumstances. Please read “—Tax Consequences of Unit Ownership—Tax Rates.”

For purposes of calculating gain or loss on the sale of units, the unitholder’s adjusted tax basis will be adjusted by its allocable share of our income or loss in respect of its units for the year of the sale. Furthermore, as described above, the IRS has ruled that a partner who acquires interests in a partnership in separate transactions must combine those interests and maintain a single adjusted tax basis for all of those interests. Upon a sale or other disposition of less than all of those interests, a portion of that tax basis must be allocated to the interests sold using an “equitable apportionment” method, which generally means that the tax basis allocated to the interest sold equals an amount that bears the same relation to the partner’s tax basis in its entire interest in the partnership as the value of the interest sold bears to the value of the partner’s entire interest in the partnership.

Treasury Regulations under Section 1223 of the Code allow a selling common unitholder who can identify units transferred with an ascertainable holding period to elect to use the actual holding period of the units transferred. Thus, according to the ruling discussed in the paragraph above, a unitholder will be unable to select high or low basis units to sell as would be the case with corporate stock, but, according to the Treasury Regulations, it may designate specific units sold for purposes of determining the holding period of the units transferred. A unitholder electing to use the actual holding period of units transferred must consistently use that

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identification method for all subsequent sales or exchanges of our units. A unitholder considering the purchase of additional units or a sale of units purchased in separate transactions is urged to consult its tax advisor as to the possible consequences of this ruling and application of the Treasury Regulations.

Specific provisions of the Code affect the taxation of some financial products and securities, including partnership interests, by treating a taxpayer as having sold an “appreciated” financial position, including a partnership interest with respect to which gain would be recognized if it were sold, assigned or terminated at its fair market value, in the event the taxpayer or a related person enters into:

Moreover, if a taxpayer has previously entered into a short sale, an offsetting notional principal contract or a futures or forward contract with respect to the partnership interest, the taxpayer will be treated as having sold that position if the taxpayer or a related person then acquires the partnership interest or substantially identical property. The Secretary of the Treasury is authorized to issue Treasury Regulations that treat a taxpayer that enters into transactions or positions that have substantially the same effect as the preceding transactions as having constructively sold the financial position.

Allocations Between Transferors and Transferees

In general, our taxable income or loss will be determined annually, will be prorated on a monthly basis and will be subsequently apportioned among the common unitholders in proportion to the number of units owned by each of them as of the opening of the applicable exchange on the first business day of the month (the “Allocation Date”). However, gain or loss realized on a sale or other disposition of our assets or, in the discretion of the general partner, any other extraordinary item of income, gain, loss or deduction will be allocated among the common unitholders on the Allocation Date in the month in which such income, gain, loss or deduction is recognized. As a result, a common unitholder transferring units may be allocated income, gain, loss and deduction realized after the date of transfer.

Although simplifying conventions are contemplated by the Code and most publicly traded partnerships use similar simplifying conventions, the use of this method may not be permitted under existing Treasury Regulations. Recently, however, the Department of the Treasury and the IRS issued final Treasury Regulations pursuant to which a publicly traded partnership may use a similar monthly simplifying convention to allocate tax items among transferor and transferee unitholders. The Partnership is currently evaluating these regulations, which apply beginning with our taxable year that begins on January 1, 2016. Nonetheless, the regulations do not specifically authorize the use of the proration method we have adopted. Accordingly, Vinson & Elkins L.L.P. is unable to opine on the validity of this method of allocating income and deductions between transferee and transferor common unitholders. If our method is not allowed under the final Treasury Regulations, or only applies to transfers of less than all of the common unitholder’s interest, our taxable income or losses could be reallocated among our common unitholders. We are authorized to revise our method of allocation between transferee and transferor common unitholders, as well as among common unitholders whose interests vary during a taxable year, to conform to a method permitted under future Treasury Regulations.

A common unitholder who disposes of units prior to the record date set for a cash distribution for that quarter will be allocated items of our income, gain, loss and deduction attributable to the month of disposition but will not be entitled to receive a cash distribution for that period.

Notification Requirements

A common unitholder who sells or purchases any units is generally required to notify us in writing of that transaction within 30 days after the transaction (or, if earlier, January 15 of the year following the transaction in

the case of a seller). Upon receiving such notifications, we are required to notify the IRS of that transaction and

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to furnish specified information to the transferor and transferee. Failure to notify us of a transfer of units may, in some cases, lead to the imposition of penalties. However, these reporting requirements do not apply to a sale by an individual who is a citizen of the United States and who effects the sale through a broker who will satisfy such requirements.

Constructive Termination

We will be considered to have “constructively” terminated as a partnership for federal income tax purposes upon the sale or exchange of 50% or more of the total interests in our capital and profits within a twelve-month period. Anadarko currently directly or indirectly owns more than 50% of the total interests in our capital and profits. Therefore, a transfer of all or a portion of Anadarko’s direct or indirect interests in us, along with transfers by other unitholders, could result in a termination of our partnership for federal income tax purposes. For purposes of measuring whether the 50% threshold is reached, multiple sales of the same unit are counted only once. A constructive termination results in the closing of our taxable year for all unitholders. In the case of a common unitholder reporting on a taxable year other than the calendar year, the closing of our taxable year may result in more than twelve months of our taxable income or loss being includable in such common unitholder’s taxable income for the year of termination.

A constructive termination occurring on a date other than December 31 generally would require that we file two tax returns for one fiscal year thereby increasing our administration and tax preparation costs. However, pursuant to an IRS relief procedure, the IRS may allow a constructively terminated partnership to provide a single Schedule K-1 for the calendar year in which a termination occurs. Following a constructive termination, we would be required to make new tax elections, including a new election under Section 754 of the Code, and the termination would result in a deferral of our deductions for depreciation and thus increase the taxable income allocable to unitholders. A termination could also result in penalties if we were unable to determine that the termination had occurred. Moreover, a termination may either accelerate the application of, or subject us to, any tax legislation enacted before the termination that would not otherwise have been applied to us as a continuing as opposed to a terminating partnership.

Uniformity of Units

Because we cannot match transferors and transferees of units and other reasons, we must maintain uniformity of the economic and tax characteristics of the units to a purchaser of these units. In the absence of uniformity, we may be unable to completely comply with a number of federal income tax requirements. Any non-uniformity could have a negative impact on the value of the units. Please read “—Tax Consequences of Unit Ownership-Section 754 Election.”

Our partnership agreement permits our general partner to take positions in filing our tax returns that preserve the uniformity of our units. These positions may include reducing the depreciation, amortization or loss deductions to which a unitholder would otherwise be entitled or reporting a slower amortization of Section 743(b) adjustments for some unitholders than that to which they would otherwise be entitled. Vinson & Elkins L.L.P. is unable to opine as to the validity of such filing positions.

A common unitholder’s basis in units is reduced by its share of our deductions (whether or not such deductions were claimed on an individual income tax return) so that any position that we take that understates deductions will overstate the unitholder’s basis in its units, and may cause the unitholder to understate gain or overstate loss on any sale of such units. Please read “—Disposition of Units-Recognition of Gain or Loss” above and “—Tax Consequences of Unit Ownership-Section 754 Election” above. The IRS may challenge one or more of any positions we take to preserve the uniformity of units. If such a challenge were sustained, the uniformity of units might be affected, and, under some circumstances, the gain from the sale of units might be increased without the benefit of additional deductions.

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Tax-Exempt Organizations and Other Investors

Ownership of units by employee benefit plans and other tax-exempt organizations as well as by non-resident alien individuals, non-U.S. corporations and other non-U.S. persons (collectively, “Non-U.S. Unitholders”) raises issues unique to those investors and, as described below, may have substantially adverse tax consequences to them. Prospective unitholders that are tax-exempt entities or non-U.S. unitholders should consult their tax advisors before investing in our units. Employee benefit plans and most other tax-exempt organizations, including IRAs and other retirement plans, are subject to federal income tax on unrelated business taxable income. Virtually all of our income will be unrelated business taxable income and will be taxable to a tax-exempt unitholder.

Non-U.S. unitholders are taxed by the United States on income effectively connected with the conduct of a U.S. trade or business (“effectively connected income”) and on certain types of U.S.-source non-effectively connected income (such as dividends), and unless exempted or further limited by an income tax treaty, will be considered to be engaged in business in the United States because of their ownership of our units. Furthermore, it is probable that they will be deemed to conduct such activities through permanent establishments in the United States within the meaning of applicable tax treaties. Consequently, they will be required to file federal tax returns to report their share of our income, gain, loss or deduction and pay federal income tax on their share of our net income or gain in a manner similar to a taxable U.S. unitholder. Moreover, under rules applicable to publicly traded partnerships, distributions to non-U.S. unitholders are subject to withholding at the highest applicable effective tax rate. Each non-U.S. unitholder must obtain a taxpayer identification number from the IRS and submit that number to our transfer agent on a Form W-8BEN, W-8BEN-E or applicable substitute form in order to obtain credit for these withholding taxes.

In addition, because a non-U.S. unitholder classified as a corporation will be treated as engaged in a United States trade or business, that corporation may be subject to the U.S. branch profits tax at a rate of 30%, in addition to regular federal income tax, on its share of our income and gain as adjusted for changes in the foreign corporation’s “U.S. net equity” to the extent reflected in the corporation’s effectively connected earnings and profits. That tax may be reduced or eliminated by an income tax treaty between the United States and the country in which the foreign corporate unitholder is a “qualified resident.” In addition, this type of unitholder is subject to special information reporting requirements under Section 6038C of the Code.

A non-U.S. unitholder who sells or otherwise disposes of a unit will be subject to federal income tax on gain realized from the sale or disposition of that unit to the extent the gain is effectively connected with a U.S. trade or business of the non-U.S. unitholder. Under a ruling published by the IRS interpreting the scope of “effectively connected income,” gain recognized by a non-U.S. person from the sale of its interest in a partnership that is engaged in a trade or business in the United States will be considered to be effectively connected with a U.S. trade or business. Thus, part or all of a non-U.S. unitholder’s gain from the sale or other disposition of its units may be treated as effectively connected with a unitholder’s indirect U.S. trade or business constituted by its investment in us. Moreover, under the Foreign Investment in Real Property Tax Act, a non-U.S. unitholder generally will be subject to federal income tax upon the sale or disposition of a unit if (i) it owned (directly or indirectly constructively applying certain attribution rules) more than 5% of our units at any time during the five-year period ending on the date of such disposition and (ii) 50% or more of the fair market value of our worldwide real property interests and our other assets used or held for use in a trade or business consisted of U.S. real property interests (which include U.S. real estate (including land, improvements, and certain associated personal property) and interests in certain entities holding U.S. real estate) at any time during the shorter of the period during which such unitholder held the units or the five-year period ending on the date of disposition. Currently, more than 50% of our assets consist of U.S. real property interests and we do not expect that to change in the foreseeable future. Therefore, non-U.S. unitholders may be subject to federal income tax on gain from the sale or disposition of their units.

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Administrative Matters

Information Returns and Audit Procedures

We intend to furnish to each common unitholder, within 90 days after the close of each taxable year, specific tax information, including a Schedule K-1, which describes its share of our income, gain, loss and deduction for our preceding taxable year. In preparing this information, which will not be reviewed by counsel, we will take various accounting and reporting positions, some of which have been mentioned earlier, to determine each common unitholder’s share of income, gain, loss and deduction. We cannot assure our common unitholders that those positions will yield a result that conforms to all of the requirements of the Code, Treasury Regulations or administrative interpretations of the IRS.

The IRS may audit our federal income tax information returns. Neither we nor Vinson & Elkins L.L.P. can assure prospective common unitholders that the IRS will not successfully challenge the positions we adopt, and such a challenge could adversely affect the value of the units. Adjustments resulting from an IRS audit may require each common unitholder to adjust a prior year’s tax liability and may result in an audit of the unitholder’s own return. Any audit of a common unitholder’s return could result in adjustments unrelated to our returns.

Publicly traded partnerships generally are treated as entities separate from their owners for purposes of federal income tax audits, judicial review of administrative adjustments by the IRS and tax settlement proceedings. The tax treatment of partnership items of income, gain, loss and deduction are determined in a partnership proceeding rather than in separate proceedings of the partners. The Code requires that one partner be designated as the “Tax Matters Partner” for these purposes, and our partnership agreement designates our general partner.

The Tax Matters Partner has made and will make some elections on our behalf and on behalf of common unitholders. The Tax Matters Partner can extend the statute of limitations for assessment of tax deficiencies against common unitholders for items in our returns. The Tax Matters Partner may bind a common unitholder with less than a 1% profits interest in us to a settlement with the IRS unless that common unitholder elects, by filing a statement with the IRS, not to give that authority to the Tax Matters Partner. The Tax Matters Partner may seek judicial review, by which all the common unitholders are bound, of a final partnership administrative adjustment and, if the Tax Matters Partner fails to seek judicial review, judicial review may be sought by any common unitholder having at least a 1% interest in profits or by any group of common unitholders having in the aggregate at least a 5% interest in profits. However, only one action for judicial review may go forward, and each common unitholder with an interest in the outcome may participate in that action.

A common unitholder must file a statement with the IRS identifying the treatment of any item on its federal income tax return that is not consistent with the treatment of the item on our return. Intentional or negligent disregard of this consistency requirement may subject a common unitholder to substantial penalties.

Nominee Reporting

Persons who hold an interest in us as a nominee for another person are required to furnish to us:

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Brokers and financial institutions are required to furnish additional information, including whether they are U.S. persons and specific information on units they acquire, hold or transfer for their own account. A penalty of $250 per failure, up to a maximum of $3 million per calendar year, is imposed by the Code for failure to report that information to us. The nominee is required to supply the beneficial owner of the units with the information furnished to us.

Accuracy-Related Penalties

Certain penalties may be imposed on taxpayers as a result of an underpayment of tax that is attributable to one or more specified causes, including negligence or disregard of rules or regulations, substantial understatements of income tax and substantial valuation misstatements. No penalty will be imposed, however, for any portion of any such underpayment if it is shown that there was a reasonable cause for the underpayment of that portion and that the taxpayer acted in good faith regarding the underpayment of that portion. Penalties may also be imposed for engaging in transactions without economic substance. We do not anticipate engaging in transactions without economic substance or otherwise participating in transactions that would subject our unitholders to accuracy-related penalties.

State, Local, Non-U.S. and Other Tax Considerations

In addition to federal income taxes, common unitholders may be subject to other taxes, including state and local and non-U.S. income taxes, unincorporated business taxes, and estate, inheritance or intangibles taxes that may be imposed by the various jurisdictions in which we conduct business or own property or in which the common unitholder is a resident. Moreover, we may also own property or do business in other states in the future that impose income or similar taxes on nonresident individuals. Although an analysis of those various taxes is not presented here, each prospective common unitholder should consider their potential impact on its investment in us.

Although you may not be required to file a return and pay taxes in some jurisdictions because your income from that jurisdiction falls below the filing and payment requirement, you will be required to file income tax returns and to pay income taxes in many of these jurisdictions in which we do business or own property and may be subject to penalties for failure to comply with those requirements. Some of the jurisdictions may require us, or we may elect, to withhold a percentage of income from amounts to be distributed to a unitholder who is not a resident of the jurisdiction. Withholding, the amount of which may be greater or less than a particular unitholder’s income tax liability to the jurisdiction, generally does not relieve a nonresident unitholder from the obligation to file an income tax return.

It is the responsibility of each common unitholder to investigate the legal and tax consequences, under the laws of pertinent jurisdictions, of its investment in us. We strongly recommend that each prospective common unitholder consult, and depend on, its own tax counsel or other advisor with regard to those matters. Further, it is the responsibility of each common unitholder to file all state, local, and non-U.S., as well as U.S. federal tax returns that may be required of it. Vinson & Elkins L.L.P. has not rendered an opinion on the state, local, alternative minimum tax or non-U.S. tax consequences of an investment in us.

Tax Consequences of Ownership of Debt Securities

A description of the material U.S. federal income tax consequences of the acquisition, ownership and disposition of debt securities will be set forth on the prospectus supplement relating to the offering of debt securities.

Tax Consequences of Ownership of Preferred Units

A description of the material U.S. federal income tax consequences of the acquisition, ownership and disposition of preferred units will be set forth on the prospectus supplement relating to the offering of preferred units.

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INVESTMENT IN OUR COMMON UNITS, PREFERRED UNITS OR DEBT SECURITIES BY EMPLOYEE BENEFIT PLANS

The following is a summary of certain considerations associated with an investment in our common units, preferred units or debt securities by employee benefit plans that are subject to the fiduciary responsibility and prohibited transaction provisions of the Employee Retirement Income Security Act of 1974, as amended (“ERISA”), the prohibited transaction restrictions imposed by Section 4975 of the Code or provisions under any federal, state, local, non-U.S. or other laws or regulations that are similar to such provisions of the Code or ERISA (collectively, “Similar Laws”). As used herein, the term “employee benefit plan” includes, but is not limited to, qualified pension, profit-sharing and stock bonus plans, certain Keogh plans, certain simplified employee pension plans and tax deferred annuities, individual retirement accounts (“IRAs”) and other arrangements established or maintained by an employer or employee organization, and entities whose underlying assets are considered to include “plan assets” of such plans, accounts and arrangements.

This summary is based on the provisions of ERISA and the Code (and related regulations and administrative and judicial interpretations) as of the date of this prospectus. This summary does not purport to be complete and future legislation, court decisions, administrative regulations, rulings or pronouncements could significantly modify the requirements summarized below. Any of these changes may be retroactive and may thereby apply to transactions entered into prior to the date of their enactment or release.

General Fiduciary Matters

ERISA and the Code impose certain duties on persons who are fiduciaries of an employee benefit plan that is subject to Title I of ERISA or Section 4975 of the Code (an “ERISA Plan”) and prohibit certain transactions involving the assets of an ERISA Plan and its fiduciaries or other interested parties. Under ERISA and the Code, any person who exercises any discretionary authority or control over the administration of an ERISA Plan or the management or disposition of the assets of an ERISA Plan, or who renders investment advice for a fee or other compensation to an ERISA Plan, is generally considered to be a fiduciary of the ERISA Plan.

Governmental plans (as defined in Section 3(32) of ERISA) and certain church plans (as defined in Section 3(33) of ERISA) and non-U.S. plans (as defined in Section 4(b)(4) of ERISA), while generally not subject to the fiduciary responsibility provisions of ERISA or the provisions of Section 4975 of the Code, may nevertheless be subject to local, state or other federal or non-U.S. laws that are substantially similar to ERISA and the Code. Fiduciaries of any such Plans should consult with their counsel before acquiring our common units, preferred units or debt securities.

In considering an investment in our common units, preferred units or debt securities with any portion of the assets of an employee benefit plan, a fiduciary of the employee benefit plan should consider, among other things, whether the investment is in accordance with the documents and instruments governing the employee benefit plan and the applicable provisions of ERISA, the Code or any applicable Similar Law relating to the fiduciary’s duties to the employee benefit plan, including, without limitation:

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Prohibited Transaction Issues

Section 406 of ERISA and Section 4975 of the Code prohibit employee benefit plans (and certain IRAs that are not considered part of an employee benefit plan) from engaging in specified transactions involving “plan assets” with parties that, with respect to the employee benefit plan or IRA, are “parties in interest” under ERISA or “disqualified persons” under the Code, unless an exemption is available. A party in interest or disqualified person who engages in a non-exempt prohibited transaction may be subject to excise taxes and other penalties and liabilities under ERISA and the Code. In addition, the fiduciary of an ERISA Plan that engages in such a non-exempt prohibited transaction may be subject to excise taxes, penalties and liabilities under ERISA and the Code.

The acquisition and/or holding of debt securities by an ERISA Plan with respect to which we or the initial purchasers are considered a party in interest or a disqualified person, may constitute or result in a direct or indirect prohibited transaction under Section 406 of ERISA and/or Section 4975 of the Code, unless the debt securities are acquired and held in accordance with an applicable statutory, class or individual prohibited transaction exemption. In this regard, the U.S. Department of Labor has issued prohibited transaction class exemptions, or PTCEs, that may provide exemptive relief for direct or indirect prohibited transactions resulting from the acquisition, holding and, if applicable, conversion of the debt securities. These class exemptions include, without limitation, PTCE 75-1 (respecting specified transactions involving employee benefit plans and broker-dealers, reporting dealers and banks); PTCE 84-14, as amended, (respecting transactions directed by independent qualified professional asset managers); PTCE 90-1 (respecting certain investments by insurance company pooled separate accounts); PTCE 91-38 (respecting certain investments by bank collective investment funds); PTCE 95-60 (respecting certain life insurance company general accounts); and PTCE 96-23 (respecting certain transactions determined by in-house asset managers). In addition, Section 408(b)(17) of ERISA and Section 4975(d)(20) of the Code each provide relief from the prohibited transaction provisions of ERISA and Section 4975 of the Code for certain transactions, provided that (i) neither the issuer of the securities nor any of its affiliates (directly or indirectly) have or exercise any discretionary authority or control or render any investment advice with respect to the assets of any ERISA Plan involved in the transaction and (ii) the ERISA Plan pays no more than adequate consideration in connection with the transaction. Each of these statutory exemptions and PTCEs contains conditions and limitations on its application and do not provide relief from the self-dealing prohibitions under ERISA and the Code. It should also be noted that even if the conditions specific in one or more of these exemptions are met, the scope of relief provided by these exemptions may not necessarily cover all acts that might be construed as prohibited transactions. Thus, the fiduciaries of an employee benefit plan that is considering acquiring and/or holding our debt securities in reliance on any of these, or any other, exemptions should carefully review the exemption and consult with their counsel to confirm that it is applicable. There can be no, and we do not provide any, assurance that any of these exemptions or any other exemption will be available with respect to the acquisition or holding of the debt securities, or that all of the conditions of any such exemptions will be satisfied.

Because of the foregoing, our common units, preferred units or debt securities may not be purchased or held (or converted to equity securities, in the case of any convertible debt) by any person investing “plan assets” of any employee benefit plan, unless such purchase and holding (or conversion, if any) will not constitute a non-exempt prohibited transaction under ERISA or the Code or similar violation of any applicable Similar Laws.

Representation

Accordingly, by acceptance of our common units, preferred units or debt securities, or any interest therein, each purchaser and subsequent transferee of the common units, preferred units or debt securities will be deemed to have represented and warranted that either (i) no portion of the assets used by such purchaser or transferee to acquire and hold the common units, preferred units or debt securities (or any interest therein) constitutes assets of

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any employee benefit plan or (ii) the acquisition and holding (and any conversion, if applicable) of the common units, preferred units or debt securities (or any interest therein) by such purchaser or transferee will not constitute a non-exempt prohibited transaction under Section 406 of ERISA or Section 4975 of the Code or similar violation under any applicable Similar Laws.

Plan Asset Issues

In addition to considering whether the purchase of our common units, preferred units or debt securities is a prohibited transaction, a fiduciary of an employee benefit plan should consider whether the plan will, by investing in our common units, preferred units or debt securities, be deemed to own an undivided interest in our assets, with the result that our general partner also would be a fiduciary of the plan and our operations would be subject to the regulatory restrictions of ERISA, including its prohibited transaction rules, as well as the prohibited transaction rules of the Code and any other applicable Similar Laws. In addition, if our assets are deemed to be “plan assets” under ERISA, this would result, among other things, in (a) the application of the prudence and other fiduciary responsibility standards of ERISA to investments made by us, and (b) the possibility that certain transaction in which we seek to engage could constitute “prohibited transaction” under the Code, ERISA and any other applicable Similar Laws.

The Department of Labor regulations, as modified by Section 3(42) of ERISA, provide guidance with respect to whether, in certain circumstances, the assets of an entity in which employee benefit plans acquire equity interests would be deemed “plan assets.” Under these regulations, an entity’s assets would not be considered to be “plan assets” if, among other things:

The foregoing discussion of issues arising for employee benefit plan investments under ERISA, the Code and applicable Similar Laws is general in nature and is not intended to be all inclusive, nor should it be construed as legal advice. In light of the complexity of these rules and the excise taxes, penalties and liabilities that may be imposed on persons involved in non-exempt prohibited transactions or other violations, plan fiduciaries contemplating a purchase of our common units, preferred units or debt securities should consult with their own counsel regarding the consequences of such purchase under ERISA, the Code and Similar Laws. The sale of any common units, preferred units or debt securities by or to any employee benefit plan is in no respect a representation by us or any of our affiliates or representatives that such an investment meets all relevant legal requirements with respect to investments by such employee benefit plans generally or any particular employee benefit plan, or that such an investment is appropriate for such employee benefit plans generally or any particular employee benefit plan.

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PLAN OF DISTRIBUTION

We may sell the offered securities in and outside the United States (1) through underwriters or dealers, (2) directly to purchasers, (3) through agents or (4) a combination of any of these methods. The prospectus supplement will set forth the following information:

Sale Through Underwriters or Dealers

If we use underwriters in the sale of the offered securities, the underwriters will acquire the securities for their own account. The underwriters may resell the securities from time to time in one or more transactions, including negotiated transactions, at a fixed public offering price or at varying prices determined at the time of sale. Underwriters may offer securities to the public either through underwriting syndicates represented by one or more managing underwriters or directly by one or more firms acting as underwriters. Unless we inform you otherwise in the prospectus supplement, the obligations of the underwriters to purchase the securities will be subject to certain conditions, and the underwriters will be obligated to purchase all the offered securities if they purchase any of them. The underwriters may sell securities to or through dealers, and the dealers may receive compensation in the form of discounts, concessions or commissions from the underwriters and/or commissions from the purchasers for whom they may act as agent. The underwriters may change from time to time the public offering price and any discounts, concessions or commissions allowed or reallowed or paid to dealers.

During and after an offering through underwriters, the underwriters may purchase and sell the securities in the open market. These transactions may include overallotment and stabilizing transactions and purchases to cover syndicate short positions created in connection with the offering. The underwriters may also impose a penalty bid, which means that selling concessions allowed to syndicate members or other broker-dealers for the offered securities sold for their account may be reclaimed by the syndicate if the offered securities are repurchased by the syndicate in stabilizing or covering transactions. These activities may stabilize, maintain or otherwise affect the market price of the offered securities, which may be higher than the price that might otherwise prevail in the open market. If commenced, these activities may be discontinued at any time.

If we use dealers in the sale of securities, we may sell the securities to them as principals. They may then resell those securities to the public at varying prices determined by the dealers at the time of resale. The dealers participating in any sale of the securities may be deemed to be underwriters within the meaning of the Securities Act of 1933, as amended (the “Securities Act”), with respect to any sale of these securities. We will include in the prospectus supplement the names of the dealers and the terms of the transaction.

Direct Sales and Sales Through Agents

We may sell the securities directly. In that event, no underwriters or agents would be involved. We may also sell the securities through agents we designate from time to time. In addition, we may offer securities through at-the-market transactions. In the prospectus supplement, we will name any agent involved in the offer or sale of

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the offered securities, and we will describe any commissions payable by us to the agent. Unless we inform you otherwise in the prospectus supplement, any agent will agree to use its reasonable best efforts to solicit purchases for the period of its appointment.

We may sell the securities directly to institutional investors or others who may be deemed to be underwriters within the meaning of the Securities Act with respect to any sale of those securities. We will describe the terms of any such sales in the prospectus supplement.

Delayed Delivery Contracts

If we so indicate in the prospectus supplement, we may authorize agents, underwriters or dealers to solicit offers from selected types of institutions to purchase securities from us at the public offering price under delayed delivery contracts. These contracts would provide for payment and delivery on a specified date in the future. The contracts would be subject only to those conditions described in the prospectus supplement. The prospectus supplement will describe the commission payable for solicitation of those contracts.

General Information

We may have agreements with firms, agents, dealers and underwriters to indemnify them against civil liabilities, including liabilities under the Securities Act, or to contribute with respect to payments that the firms, agents, dealers or underwriters may be required to make. Such firms, agents, dealers and underwriters may be customers of, engage in transactions with or perform services for us in the ordinary course of their businesses.

Unless otherwise indicated in the applicable prospectus supplement, each series of offered securities will be a new issue, and other than our common units, which are listed on the New York Stock Exchange, will have no established trading market. We may elect to list any series of offered securities on an exchange, but we are not obligated to do so. It is possible that one or more underwriters may make a market in a series of offered securities. However, they will not be obligated to do so and may discontinue market making at any time without notice. We cannot assure you that a liquid trading market for any of our offered securities will develop.

Because FINRA views our common units as interests in a direct participation program, any offering of common units under the registration statement of which this prospectus forms a part will be made in compliance with Rule 2310 of the FINRA Conduct Rules. Any compensation to be received by underwriters in connection with an offering of securities pursuant to this prospectus will not exceed 8% of the gross proceeds of such offering.

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LEGAL MATTERS

The validity of the issuance of and, if applicable, the material federal income tax considerations regarding, the securities offered hereby will be passed upon for us by Vinson & Elkins L.L.P. Additional legal matters may be passed on for us, or any underwriters, dealers or agents, by counsel we will name in the applicable prospectus supplement.

EXPERTS

The consolidated financial statements of Western Gas Partners, LP and subsidiaries as of December 31, 2015 and 2014, and for each of the years in the three-year period ended December 31, 2015, and management’s assessment of the effectiveness of internal control over financial reporting as of December 31, 2015, have been incorporated by reference herein in reliance upon the reports of KPMG LLP, independent registered public accounting firm, incorporated by reference herein, and upon the authority of said firm as experts in accounting and auditing. The audit report on the effectiveness of internal control over financial reporting as of December 31, 2015, expresses an opinion that Western Gas Partners, LP did not maintain effective internal control over financial reporting as of December 31, 2015 because of the effect of a material weakness on the achievement of the objectives of the control criteria and contains an explanatory paragraph that states a material weakness has been identified and included in management’s assessment related to an inadequate understanding of generally accepted accounting principles related to impairment by certain individuals and a failure to follow accounting policies, resulting in a triggering event not being identified that would have led to an asset impairment.

WHERE YOU CAN FIND MORE INFORMATION

Each time we offer to sell securities, we will provide a prospectus supplement that will contain specific information about the terms of that offering. The prospectus supplement may also add to, update or change information contained in this prospectus. This prospectus, together with the applicable prospectus supplement, will include or refer you to all material information relating to each offering.

We have filed a registration statement with the SEC under the Securities Act that registers the offer and sale by us of the securities covered by this prospectus. The registration statement, including the exhibits attached thereto and incorporated by reference therein, contains additional relevant information about us. In addition, we file annual, quarterly and other reports and other information with the SEC (File No. 001-34046). You may read and copy documents we file at the SEC’s public reference room at 100 F Street, N.E., Washington, D.C. 20549. Please call the SEC at 1-800-SEC-0330 for information on the operation of the SEC’s public reference room. The SEC maintains a website that contains reports, proxy and information statements and other information regarding issuers that file electronically with the SEC. Our SEC filings are available on the SEC’s website at http://www.sec.gov.

The SEC allows us to “incorporate by reference” the information we have filed with the SEC. This means that we can disclose important information to you without actually including the specific information in this prospectus by referring you to other documents filed separately with the SEC. The information incorporated by reference is an important part of this prospectus. Information that we later provide to the SEC, and which is deemed to be “filed” with the SEC, will automatically update information previously filed with the SEC, and may replace information in this prospectus and information previously filed with the SEC.

We incorporate by reference the documents listed below and any filings we make with the SEC under Sections 13(a), 13(c), 14, or 15(d) of the Exchange Act (excluding information deemed to be furnished and not filed with the SEC), after the date on which the registration statement of which this prospectus forms a part was initially filed with the SEC until all offerings under such registration statement are completed or terminated:

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These reports contain important information about us, our financial condition and our results of operations.

We make available free of charge on or through our website, http://www.westerngas.com , our Annual Report on Form 10-K, Quarterly Reports on Form 10-Q, Current Reports on Form 8-K and amendments to these reports filed or furnished pursuant to Section 13(a) or 15(d) of the Exchange Act as soon as reasonably practicable after we electronically file such material with, or furnish it to, the SEC. We make our website content available for information purposes only. Information contained on our website is not incorporated by reference into this prospectus and does not constitute a part of this prospectus.

You may obtain copies of any of the documents incorporated by reference in this prospectus from the SEC through the SEC’s website at the address provided above. You also may request a copy of any document incorporated by reference in this prospectus (including exhibits to those documents specifically incorporated by reference in this prospectus), at no cost, by visiting our website at http://www.westerngas.com , or by writing or calling us at the following address:

Investor Relations

Western Gas Partners, LP

1201 Lake Robbins Drive

The Woodlands, Texas 77380-1046

Telephone: (832) 636-6000

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$                    % SENIOR NOTES DUE 2028

$                    % SENIOR NOTES DUE 2048

PROSPECTUS SUPPLEMENT

Joint Book-Running Managers

Wells Fargo Securities

PNC Capital Markets LLC

RBC Capital Markets

US Bancorp

                    , 2018