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As filed with the Securities and Exchange Commission on March 4, 2008

Registration No. 333-           

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

FORM S-3
REGISTRATION STATEMENT
UNDER THE SECURITIES ACT OF 1933

PACKAGING CORPORATION OF AMERICA
(Exact name of registrant as specified in its charter)

Delaware
(State or other jurisdiction of
incorporation or organization)		   36-4277050
(I.R.S. Employer
Identification No.)

1900 West Field Court
Lake Forest, Illinois 60045
(847) 482-3000
(Address, including zip code, and telephone number, including
area code, of registrant's principal executive offices)

Kent A. Pflederer
Packaging Corporation of America
1900 West Field Court
Lake Forest, Illinois 60045
(847) 482-3000
(Name, address, including zip code, and telephone number, including area code, of agent for service)

Copies of all communications, including communications sent to agent for service, should be sent to:
James S. Rowe
Robert M. Hayward
Kirkland & Ellis LLP
200 East Randolph Drive
Chicago, Illinois 60601
(312) 861-2000

          Approximate date of commencement of proposed sale to the public: From time to time on or after the effective date of this Registration Statement.

          If the only securities being registered on this Form are being offered pursuant to dividend or interest reinvestment plans, please check the following box.    o

          If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933, other than securities offered only in connection with dividend or interest reinvestment plans, check the following box.    ý

          If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, please check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.    o

          If this Form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.    o

          If this Form is a registration statement pursuant to General Instruction I.D. or a post-effective amendment thereto that shall become effective upon filing with the Commission pursuant to Rule 462(e) under the Securities Act, check the following box.    ý

          If this Form is a post-effective amendment to a registration statement filed pursuant to General Instruction I.D. filed to register additional securities or additional classes of securities pursuant to Rule 413(b) under the Securities Act, check the following box.    o

CALCULATION OF REGISTRATION FEE

Title of Each Class of
Securities to be Registered

   Amount to
be Registered

   Proposed Maximum
Offering Price
per Unit

   Proposed Maximum
Aggregate
Offering Price

   Amount of
Registration Fee
Debt Securities   (1)   (1)   (1)   (2)
(1)
Omitted pursuant to General Instructions II.E of Form S-3. An indeterminate amount of debt securities is being registered as may from time to time be issued at indeterminate prices.

(2)
In accordance with Rules 456(b) and 457(r), the Registrant is deferring payment of the Registration Fee.

PROSPECTUS

Packaging Corporation of America

GRAPHIC

Debt Securities

Packaging Corporation of America may offer from time to time, in one or more offerings, its debt securities. This prospectus describes the general terms of these securities and the general manner in which we will offer them. We will provide the specific terms of these securities in supplements to this prospectus. The prospectus supplements will also describe the specific manner in which we will offer these securities and may also supplement, update or amend information contained in this prospectus. You should carefully read this prospectus and the applicable prospectus supplement, as well as the documents incorporated by reference herein or therein, before you invest in these securities.

We may sell these securities directly, through agents, dealers or underwriters as designated from time to time, or through a combination of these methods. We reserve the sole right to accept, and together with any agents, dealers and underwriters, reserve the right to reject, in whole or in part, any proposed purchase of securities. If any agents, dealers or underwriters are involved in the sale of any securities, the applicable prospectus supplement will set forth their names and any applicable commissions or discounts. Our net proceeds from the sale of securities also will be set forth in the applicable prospectus supplement.

See "Risk Factors" on page 1 of this prospectus to read about factors you should consider before investing in these securities.

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

The date of this prospectus is March 4, 2008.


TABLE OF CONTENTS

About this Prospectus   i
Our Company   1
Risk Factors   1
Forward-Looking Statements   1
Use of Proceeds   2
Ratio of Earning to Fixed Charges   3
Description of Debt Securities   3
Plan of Distribution   16
Legal Matters   16
Experts   16
Where You Can Find More Information   16
Incorporation of Certain Information by Reference   16


ABOUT THIS PROSPECTUS

        This prospectus is part of a shelf registration statement that we filed with the Securities and Exchange Commission (the "SEC"). By using a shelf registration statement, we may, at any time and from time to time, in one or more offerings, sell the debt securities described in this prospectus.

        This prospectus provides you with a general description of the debt securities we may offer. Each time we use this prospectus to offer debt securities, we will provide you with a prospectus supplement that will describe the specific amounts, prices and terms of the securities being offered. The prospectus supplement may also supplement, update or change information contained in this prospectus. Therefore, if there is any inconsistency between the information in this prospectus and the prospectus supplement, you should rely on the information in the prospectus supplement.

        We have not authorized anyone to provide you with different information. We are not making an offer of these securities in any jurisdiction where the offer is not permitted. You should not assume that the information in this prospectus or any applicable prospectus supplement is accurate as of any date other than the date of the document.

        To understand the terms of our debt securities, you should carefully read this prospectus and the applicable prospectus supplement. Together, they give the specific terms of the debt securities we are offering. You should also read the documents we have referred you to under "Where You Can Find More Information" below for information about us. The shelf registration statement, including the exhibits thereto, can be read at the SEC's website or at the SEC's Public Reference Room, each as described under "Where You Can Find More Information."

        The terms "PCA," "we," "us," and "our" as used in this prospectus refer to Packaging Corporation of America and its consolidated subsidiaries, unless the context otherwise requires. Packaging Corporation of America will be the issuer of the debt securities described in this prospectus. The phrase "this prospectus" refers to this prospectus and any applicable prospectus supplement, unless the context otherwise requires.

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OUR COMPANY

        PCA is the sixth largest producer of containerboard and corrugated products in the United States in terms of production capacity. With 2007 net sales of $2.3 billion, PCA produced approximately 2.4 million tons of containerboard, of which about 80% was consumed in PCA's corrugated products manufacturing plants, 12% was sold to domestic customers and 8% was sold to the export market. Our corrugated products manufacturing plants sold about 31.2 billion square feet of corrugated products.

        In 2007, we produced 1.5 million tons of kraft linerboard at our mills located in Counce, Tennessee and Valdosta, Georgia, and 0.9 million tons of semi-chemical corrugating medium at our mills located in Tomahawk, Wisconsin and Filer City, Michigan. We currently lease the cutting rights to approximately 102,000 acres of timberland located near our Counce and Valdosta mills. We also have supply agreements on approximately 370,000 acres of timberland.

        Our corrugated products manufacturing plants produce a wide variety of corrugated packaging products, including conventional shipping containers used to protect and transport manufactured goods, multi-color boxes, and displays with strong visual appeal that help to merchandise the packaged product in retail locations. In addition, we are a large producer of meat boxes and wax-coated boxes for the agricultural industry.

        Packaging Corporation of America is a Delaware corporation. Our principal executive offices are located at 1900 West Field Court, Lake Forest, Illinois 60045, and our telephone number is (847) 482-3000. Our website address is www.packagingcorp.com. This website address is not intended to be an active link and information on our website should not be construed to be part of this prospectus.


RISK FACTORS

        Our business is subject to uncertainties and risks. You should carefully consider and evaluate all of the information included and incorporated by reference in this prospectus, including the risk factors incorporated by reference from our most recent annual report on Form 10-K, as updated by our quarterly reports on Form 10-Q and other filings we make with the SEC. It is possible that our business, financial condition, liquidity or results of operations could be materially adversely affected by any of these risks.


FORWARD-LOOKING STATEMENTS

        Some of the statements contained and incorporated by reference in this prospectus that are not historical in nature may constitute forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. These statements are often identified by the words "will," "should," "anticipate," "believe," "expect," "intend," "estimate," "hope," or similar expressions. These statements reflect management's current views with respect to future events and are subject to risks and uncertainties. There are important factors that could cause actual results to differ materially from those in forward-looking statements, many of which are beyond our control. These factors, risks and uncertainties include the following:

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        Our actual results, performance or achievement could differ materially from those expressed in, or implied by, these forward-looking statements, and accordingly, we can give no assurances that any of the events anticipated by the forward-looking statements will transpire or occur, or if any of them do so, we can give no assurances of the impact that they will have on our results of operations or financial condition. In view of these uncertainties, investors are cautioned not to place undue reliance on these forward-looking statements. We expressly disclaim any obligation to publicly revise any forward-looking statements that have been made to reflect the occurrence of events after the date on which those statements are made. For a discussion of other factors that may affect our business, you should read carefully the factors discussed under "Risk Factors" in our filings incorporated by reference into this prospectus. See "Risk Factors."


USE OF PROCEEDS

        Unless otherwise indicated in the applicable prospectus supplement, we will use the net proceeds from the sale of our debt securities offered by this prospectus for the repayment of indebtedness and for general corporate and working capital purposes. We may invest the net proceeds temporarily or apply them to repay short-term or revolving debt until we use them for their stated purpose.

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RATIO OF EARNINGS TO FIXED CHARGES

        The following table sets forth our historical ratios of earnings to fixed charges for the periods indicated. This information should be read in conjunction with the consolidated financial statements and the accompanying notes incorporated by reference in this prospectus.

 
   Years Ended December 31,
 
   2007
   2006
   2005
   2004
   2003
 
   Amounts in millions, except ratios
Ratio of Earnings to Fixed Charges   6.4x   4.9x   2.9x   3.6x   1.8x
 
Details of the specific calculations are set forth below:
 
 
 
 
 
 
 
 
 
 
 
   Years Ended December 31,
  
 
   2007
   2006
   2005
   2004
   2003
  
 
   Amounts in millions, except ratios

  
Earnings                                
  Income (loss) before taxes   $ 267.9   $ 194.7   $ 88.0   $ 110.9   $ (24.9 )
  Add: Fixed charges     49.4     49.3     46.0     42.5     133.9  
   
 
 
 
 
 
  Subtotal     317.3     244.0     134.0     153.4     109.0  
  Less: Capitalized interest     (1.0 )   (0.5 )   (0.8 )   (0.5 )   (0.3 )
   
 
 
 
 
 
  Total   $ 316.3   $ 243.5   $ 133.2   $ 152.9   $ 108.7  
   
 
 
 
 
 
Fixed charges                                
  Interest expense   $ 35.1   $ 36.0   $ 33.3   $ 31.0   $ 123.1  
  Capitalized interest     1.0     0.5     0.8     0.5     0.3  
  Interest portion of rent expense (1)     13.3     12.8     11.9     11.0     10.5  
   
 
 
 
 
 
  Total     49.4     49.3     46.0     42.5     133.9  
  2003 tender offer premium     —     —     —     —     (55.9 )
  2003 write-off of deferred financing fees     —     —     —     —     (17.4 )
   
 
 
 
 
 
  Fixed charges adjusted for 2003 refinancing charges   $ 49.4   $ 49.3   $ 46.0   $ 42.5   $ 60.6  
   
 
 
 
 
 
Ratio of Earnings to Fixed Charges     6.4x     4.9x     2.9x     3.6x     1.8x  
(1)
The interest portion of rent expense represents the estimated interest component of such rental payments.

        Earnings available for fixed charges represent earnings before income taxes and fixed charges excluding capitalized interest. Fixed charges represent interest expense; amortization of a 2003 treasury lock settlement, debt discount and expenses; capitalized interest and that portion of rental expense deemed to be the equivalent of interest.


DESCRIPTION OF DEBT SECURITIES

        The debt securities covered by this prospectus will be issued under an Indenture, dated as of July 21, 2003, between us and U.S. Bank National Association, as trustee, as amended by the First Supplemental Indenture, dated as of July 21, 2003, between us and U.S. Bank, National Association, as trustee (collectively, the "indenture"). As used in this section, "PCA," "we," "us" and "our" refer to Packaging Corporation of America, the issuer of the debt securities. We have summarized certain provisions of the indenture below. The summary is not complete and is qualified in its entirety by reference to the indenture. The indenture has

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been incorporated by reference as an exhibit to the registration statement for these securities that we have filed with the SEC. In addition to the indenture described below, we may issue debt securities pursuant to another indenture or indentures to be entered into after the date of this prospectus. If we elect to issue debt securities under another indenture, we will file a copy of that indenture as an exhibit to the registration statement of which this prospectus is a part.

        When we offer to sell a particular series of debt securities, we will describe the specific terms of the securities in a supplement to this prospectus. The prospectus supplement will also indicate whether the general terms and provisions described in this prospectus apply to a particular series of debt securities.

        You should carefully read the summary below, the applicable prospectus supplements and the provisions of the indenture that may be important to you.

        For a summary of some of the defined terms used in the indenture, see "—Defined Terms."

General

        The indenture does not limit the amount of debt securities that we may issue. We may issue debt securities up to an aggregate principal amount as we may authorize from time to time in one or more series. Under the indenture, we may issue debt securities with terms different from those of debt securities that we have previously issued. We may issue additional amounts of a series of debt securities without the consent of the holders of that series. The different series of debt securities issued under the indenture may have different dates for payments, different rates of interest and be denominated in different currencies.

        The applicable prospectus supplement relating to a series of debt securities being offered will describe the specific terms of those debt securities, including the following:

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        Prospective purchasers of debt securities should be aware that special United States federal income tax, accounting and other considerations not addressed in this prospectus may be applicable to the debt securities. The prospectus supplement relating to an issue of debt securities will describe these considerations, if they apply.

Covenants

        The indenture contains, among others, the following covenants. The indenture permits us to delete or modify the following covenants with respect to any series of debt securities we issue, and also add to the following covenants with respect to any such series. We will describe the specific covenants applicable to debt securities we issue in the applicable prospectus supplement.

        Limitations on Liens.    The indenture provides that we may not, and may not permit any Restricted Subsidiary to, create or suffer to exist any Lien to secure any Indebtedness of ours or any of our Subsidiaries upon any Principal Property, or upon shares of capital stock or evidences of Indebtedness issued by any Restricted Subsidiary and owned by us or any

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Restricted Subsidiary (whether such Principal Property, shares or evidences of indebtedness were owned as of the date of the indenture or thereafter acquired), without making, or causing such Restricted Subsidiary to make, effective provision to secure all of the debt securities issued under the indenture from time to time outstanding by such Lien, equally and ratably with, or prior to, any and all other Indebtedness thereby secured, so long as such Indebtedness is so secured, unless, after giving effect thereto, the sum of (a) the principal amount of Indebtedness secured by all Liens incurred after the date of the indenture to the extent the incurrence of such Indebtedness (i) did not require us or any Restricted Subsidiary to equally and ratably secure the debt securities or (ii) was not otherwise permitted by the next succeeding paragraph and (b) the Attributable Value of all Sale and Leaseback Transactions entered into after the date of the indenture (other than (i) the Attributable Value in respect of any such Sale and Leaseback Transactions the Net Available Proceeds from which are applied as set forth in the second bullet under "—Limitations on Sale and Leaseback Transactions" or (ii) the Attributable Value in respect of any Permitted Transactions (as defined under "—Limitations on Sale and Leaseback Transactions")), does not exceed 10% of our Consolidated Net Tangible Assets.

        The foregoing restrictions shall not apply to Indebtedness secured by Liens existing on the date of the indenture or to:

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        Limitations on Sale and Leaseback Transactions.    The indenture provides that we may not, and may not permit any Restricted Subsidiary to, enter into any Sale and Leaseback Transaction with respect to any Principal Property, unless:

        The foregoing restrictions will not apply to the following Sale and Leaseback Transactions (each, a "Permitted Transaction"):

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Consolidation, Merger and Sale of Assets

        The indenture provides that we shall not consolidate with or merge into any other person or sell, assign, transfer, lease or otherwise convey our properties and assets substantially as an entirety to any person unless:

        Upon any consolidation with or merger into any other person or any sale, assignment, transfer, lease or other conveyance of our properties and assets substantially as an entirety to any person, the successor person formed by such consolidation or into which we are merged or to which such sale, assignment, transfer, lease or other conveyance is made shall succeed to, and be substituted for, and may exercise every right and power of, ours under the indenture and, in the event of any such sale, assignment, transfer or other conveyance, we, except in the case of a lease, shall be discharged of all obligations and covenants under the indenture and the debt securities and may be dissolved and liquidated.

Defined Terms

        Set forth below is a summary of some of the defined terms used in the indenture. Reference is made to the indenture for the full definition of all such terms, as well as any other terms used in this prospectus for which no definition is provided.

        "Attributable Value" in respect of any Sale and Leaseback Transaction means, as of the time of determination, the lesser of:

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        "Consolidated Net Tangible Assets" means the aggregate amount of the assets (less applicable reserves and other properly deductible items) of us and our Subsidiaries after deducting therefrom (a) all current liabilities (excluding any indebtedness for money borrowed having a maturity of less than 12 months from the date of our most recent consolidated balance sheet but which by its terms is renewable or extendible beyond 12 months from that date at the option of the borrower) of us and our Subsidiaries and (b) all goodwill, trade names, patents, unamortized debt discount and expense and any other like intangibles of us and our Subsidiaries, all as set forth on our most recent consolidated balance sheet and computed in accordance with accounting principles generally accepted in the United States of America.

        "Indebtedness" means (without duplication), with respect to any person:

        "Lien" means, with respect to any property or assets, any mortgage or deed of trust, pledge, hypothecation, assignment, security interest, lien, encumbrance or other security arrangement of any kind or nature whatsoever on or with respect to such property or assets (including any conditional sale or other title retention agreement having substantially the same economic effect as any of the foregoing).

        "Net Available Proceeds" from any Sale and Leaseback Transaction by any person means cash or readily marketable cash equivalents received (including by way of sale or discounting of a note, installment receivable or other receivable, but excluding any other consideration received in the form of assumption by the acquiree of Indebtedness or obligations relating to the properties or assets that are the subject of such Sale and Leaseback Transaction or received in any other noncash form) therefrom by such person, net of (a) all legal, title and recording tax expenses, commissions and other fees and expenses incurred and all Federal, state, provincial, foreign and local taxes required to be accrued as a liability as a consequence of such Sale and Leaseback Transaction; (b) all payments made by such person or its Subsidiaries on any Indebtedness which is secured in whole or in part by any such properties and assets in accordance with the terms of any Lien upon or with respect to any such properties and assets or which must, by the terms of such Lien, or in order to obtain a necessary consent to such Sale and Leaseback Transaction or by applicable law, be repaid out

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of the proceeds from such Sale and Leaseback Transaction; and (c) all distributions and other payments made to minority interest holders in Subsidiaries of such person or joint ventures as a result of such Sale and Leaseback Transaction.

        "Principal Property" means any real property or any permanent improvement thereon located in the United States owned by PCA or any of its Subsidiaries, including, without limitation, any (a) timber property or (b) warehouse, manufacturing or processing plant, building, structure or other facility (or any portion thereof, and any equipment located at or comprising a part of any such property) having a net book value, as of the date of determination, in excess of 1.0% of our Consolidated Net Tangible Assets.

        "Restricted Subsidiary" means any Subsidiary of PCA in which (a) PCA and its other Subsidiaries' aggregate investments in and advances to such Subsidiary exceed 10% of the total assets of PCA and its Subsidiaries consolidated as of the end of the most recently completed fiscal year; or (b) PCA and its other Subsidiaries' proportionate share of the total assets of such Subsidiary exceeds 10% of the total assets of PCA and its Subsidiaries consolidated as of the end of the most recently completed fiscal year; or (c) PCA and its other Subsidiaries' equity in the income from continuing operations before taxes, extraordinary items and cumulative effect of a change in accounting principle of such Subsidiary exceeds 10% of such income of PCA and its Subsidiaries consolidated for the most recently completed fiscal year.

        "Sale and Leaseback Transaction" of any person means an arrangement with any lender or investor or to which such lender or investor is a party providing for the leasing by such person of any Principal Property that, more than 12 months after (a) the completion of the acquisition, construction, development or improvement of such Principal Property or (b) the placing in operation of such Principal Property or of such Principal Property as so constructed, developed or improved, has been or is being sold, conveyed, transferred or otherwise disposed of by such person to such lender or investor or to any person to whom funds have been or are to be advanced by such lender on the security of such Principal Property. The term of such arrangement, as of any date (the "measurement date"), shall end on the date of the last payment of rent or any other amount due under such arrangement on or prior to the first date after the measurement date on which such arrangement may be terminated by the lessee, at its sole option without payment of a penalty.

        "Subsidiary" of any person means a person more than 50% of the outstanding voting interests in which are owned, directly or indirectly, by such person or by one or more other Subsidiaries of such person or by such person and one or more Subsidiaries thereof.

Events of Default

        An "Event of Default" with respect to the debt securities of any series is defined in the indenture as being:

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        The indenture permits us to delete, modify or add to the preceding Events of Default with respect to any series of debt securities, and an Event of Default with respect to a series of debt securities does not necessarily constitute an Event of Default with respect to any other series of debt securities. Any additional or different Events of Default with respect to a particular series of debt securities will be described in the applicable prospectus supplement. The indenture provides that the trustee may withhold notice to the holders of the debt securities of any series of the occurrence of a default with respect to the debt securities of that series (except for a default in the payment of principal, premium, if any, or interest) if the trustee in good faith determines it to be in the interest of the holders to do so.

        If an Event of Default with respect to the debt securities of any series occurs and is continuing, either the trustee or the holders of at least 25% of the aggregate principal amount of the outstanding debt securities of that series may declare the principal of all the debt securities of that series, or of such lesser amount as may be provided for in the debt securities of such series, and accrued and unpaid interest, if any, thereon, to be due and payable immediately. At any time after the debt securities of any series have been accelerated, but before a judgment or decree for payment of money due has been obtained, the holders of a majority of the aggregate principal amount of outstanding debt securities of that series may, under certain circumstances, rescind and annul such acceleration. An Event of Default relating to our bankruptcy, insolvency or reorganization shall cause the principal amount and accrued interest to become immediately due and payable without any declaration or other act by the trustee or holder of the debt securities. For information as to waiver of defaults, see "—Modification, Waivers and Meetings" below.

        The indenture provides that, subject to the duty of the trustee during a default to act with the required standard of care, the trustee will be under no obligation to exercise any of its rights or powers under the indenture at the request or direction of any of the holders of debt securities of any series unless such holders shall have offered to the trustee reasonable security or indemnity. Subject to the foregoing, the holders of a majority of the aggregate principal amount of the outstanding debt securities of any series will have the right, subject to certain limitations, to direct the time, method and place of conducting any proceeding for any remedy available to the trustee under the indenture with respect to the debt securities of that series.

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        No holder of any debt securities of any series will have any right to institute any proceeding with respect to the indenture or for any remedy thereunder unless:

        Notwithstanding the provisions described in the immediately preceding paragraph or any other provision of the indenture, the holder of any debt security shall have the right, which is absolute and unconditional, to receive payment of the principal of and premium, if any, and interest on such debt security on the respective dates such payments are due and to institute suit for enforcement of any such payment, and such right shall not be impaired without the consent of such holder.

Modification, Waivers and Meetings

        The indenture contains provisions permitting us and the trustee, with the consent of the holders of a majority in principal amount of the outstanding debt securities of each series issued under the indenture that is affected by the modification or amendment, to modify or amend any of the provisions of the indenture or of the debt securities of such series or the rights of the holders of the debt securities of such series under the indenture, provided that no such modification or amendment shall, among other things:

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without in each such case obtaining the consent of the holder of each outstanding debt security issued under the indenture so affected.

        The indenture also contains provisions permitting us and the trustee, without notice to or the consent of the holders of any debt securities issued thereunder, to modify or amend the indenture in order to, among other things:

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        The holders of a majority in aggregate principal amount of the outstanding debt securities of any series may, on behalf of all holders of debt securities of that series, waive our compliance with certain restrictive provisions of the indenture, including the covenants described above under "—Covenants—Limitations on Liens" and "—Limitations on Sale and Leaseback Transactions." The holders of a majority in aggregate principal amount of the outstanding debt securities of any series may, on behalf of all holders of debt securities of that series, waive any past default under the indenture with respect to debt securities of that series and its consequences, except a default in the payment of the principal of, or premium, if any, or interest on any debt securities of such series or in respect of a covenant or provision which cannot be modified or amended without the consent of the holder of each outstanding debt security of such series affected.

        The indenture contains provisions for convening meetings of the holders of debt securities of a series issued thereunder. A meeting may be called at any time by the trustee and also, upon request, by us or the holders of at least 10% in principal amount of the outstanding debt securities of such series, in any such case upon notice given in accordance with the provisions of the indenture. Except for any consent which must be given by the holder of each outstanding debt security affected thereby, as described above, any resolution presented at a meeting or adjourned meeting duly reconvened at which a quorum is present may be adopted only by the affirmative vote of the holders of a majority in principal amount of the outstanding debt securities of that series; provided, however, that any resolution with respect to any request, demand, authorization, direction, notice, consent, waiver or other action which the indenture expressly provides may be made, given or taken by the holders of a specified percentage, other than a majority, in principal amount of the outstanding debt securities of a series may be adopted at a meeting or adjourned meeting duly reconvened at which a quorum is present by the affirmative vote of the holders of such specified percentage in principal amount of the outstanding debt securities of that series. Any resolution passed or decision taken at any meeting of holders of debt securities of any series duly held in accordance with the indenture will be binding on all holders of debt securities of that series whether or not such holders were present or represented at the meeting. The quorum at any meeting called to adopt a resolution, and at any reconvened meeting, will be persons holding or representing a majority in principal amount of the outstanding debt securities of a series, subject to certain exceptions.

        In determining whether the holders of the requisite principal amount of the outstanding debt securities of any series have given any request, demand, authorization, direction, notice, consent or waiver under the indenture, any debt security of that series owned by us or any

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other obligor on such debt securities or any of our affiliates or such other obligor will be deemed not to be outstanding.

Defeasance and Covenant Defeasance

        When we use the term defeasance, we mean discharge from some or all of our obligations under the indenture. If we deposit with the trustee sufficient cash or government securities to pay the principal, interest and any other sums due to the stated maturity date of the debt securities, then at our option:


        If this happens, the holders of the debt securities will not be entitled to the benefits of the indenture, except for registration of transfer and exchange thereof, and replacement of those that are lost, stolen or mutilated. These holders may look only to those deposited funds or obligations for payment.

        We must deliver to the trustee an opinion of counsel to the effect that the deposit and related defeasance would not cause the holders of the debt securities to recognize income, gain or loss for United States federal income tax purposes.

Governing Law

        The indenture is, and the debt securities will be, governed by the laws of the State of New York.

Trustee

        U.S. Bank National Association is the trustee under the indenture.

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PLAN OF DISTRIBUTION

        We may sell the debt securities offered pursuant to this prospectus in any of the following ways:

        We will identify the specific plan of distribution, including any underwriters, brokers, dealers, agents or direct purchasers and their compensation in a prospectus supplement.


LEGAL MATTERS

        The validity of the debt securities offered pursuant to this prospectus and any prospectus supplement will be passed upon for us by Kirkland & Ellis LLP, Chicago, Illinois, and for any underwriters or agents by counsel named in the applicable prospectus supplement.


EXPERTS

        The consolidated financial statements of Packaging Corporation of America appearing in Packaging Corporation of America's Annual Report (Form 10-K) for the fiscal year ended December 31, 2007 (including Schedule II appearing therein) and the effectiveness of Packaging Corporation of America's internal control over financial reporting as of December 31, 2007, have been audited by Ernst & Young LLP, independent registered public accounting firm, as set forth in their reports thereon, included therein, and incorporated herein by reference. Such consolidated financial statements are incorporated herein by reference in reliance upon such reports given on the authority of such firm as experts in accounting and auditing.


WHERE YOU CAN FIND MORE INFORMATION

        We file periodic reports, proxy statements and other information with the Securities and Exchange Commission. You may read and copy (at prescribed rates) any such reports, proxy statements and other information at the SEC's Public Reference Room at 100 F Street, N.E., Washington, D.C. 20549. For further information concerning the SEC's Public Reference Room, you may call the SEC at 1-800-SEC-0330. Some of this information may also be accessed on the World Wide Web through the SEC's Internet address at http://www.sec.gov. This website address is not intended to be an active link.


INCORPORATION OF CERTAIN INFORMATION BY REFERENCE

        The SEC allows us to "incorporate by reference" information into this prospectus, which means that we can disclose important information about us by referring you to another document filed separately with the SEC. The information incorporated by reference is considered to be a part of this prospectus. This prospectus incorporates by reference the documents and reports listed below (other than portions of these documents that are furnished under Item 2.02 or Item 7.01 of a Current Report on Form 8-K, including any exhibits included with such Items):

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        We also incorporate by reference the information contained in all other documents we file with the SEC pursuant to Sections 13(a), 13(c), 14 or 15(d) of the Securities Exchange Act of 1934 (other than portions of these documents that are furnished under Item 2.02 or Item 7.01 of a Current Report on Form 8-K, including any exhibits included with such Items, unless otherwise indicated therein) after the date of this prospectus and prior to the termination of this offering. The information contained in any such document will be considered part of this prospectus from the date the document is filed with the SEC.

        Any statement contained in this prospectus or in a document incorporated or deemed to be incorporated by reference in this prospectus will be deemed to be modified or superseded to the extent that a statement contained herein or in any other subsequently filed document which also is or is deemed to be incorporated by reference in 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.

        We undertake to provide without charge to any person, including any beneficial owner, to whom a copy of this prospectus is delivered, upon oral or written request of such person, a copy of any or all of the documents that have been incorporated by reference in this prospectus, other than exhibits to such other documents (unless such exhibits are specifically incorporated by reference therein). We will furnish any exhibit not specifically incorporated by reference upon the payment of a specified reasonable fee, which fee will be limited to our reasonable expenses in furnishing such exhibit. All requests for such copies should be directed to Kent A. Pflederer, Packaging Corporation of America, 1900 West Field Court, Lake Forest, Illinois 60045, (847) 482-3000.

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PART II

INFORMATION NOT REQUIRED IN PROSPECTUS

Item 14.    Other Expenses of Issuance and Distribution.

        The following is a statement of the estimated expenses, to be paid solely by Packaging Corporation of America, of the issuance and distribution of the securities being registered hereby:

Securities and Exchange Commission registration fee   (1 )
Printing expenses   (2 )
Accounting fees and expenses   (2 )
Legal fees and expenses   (2 )
Rating agency fees and expenses   (2 )
Trustee's fees and expenses (including counsel's fees)   (2 )
Miscellaneous expenses   (2 )
  Total   (2 )
(1)
In accordance with Rules 456(b) and 457(r), we are deferring payment of the registration fee.

(2)
An estimate of the aggregate amount of these expenses will be reflected in the applicable prospectus supplement.

Item 15.   Indemnification of Directors and Officers.

Delaware General Corporation Law

        Section 145 of the Delaware General Corporation Law (the "DGCL") provides that a corporation may indemnify any person who was or is a party or is threatened to be made a party to any threatened, pending or completed action, suit or proceeding, whether civil, criminal, administrative or investigative (other than an action by or in the right of the corporation) by reason of the fact that the person is or was a director, officer, employee or agent of the corporation, or is or was serving at the request of the corporation as a director, officer, employee or agent of another corporation, partnership, joint venture, trust or other enterprise, against expenses (including attorneys' fees), judgments, fines and amounts paid in settlement actually and reasonably incurred by the person in connection with such action, suit or proceeding if the person acted in good faith and in a manner the person reasonably believed to be in or not opposed to the best interests of the corporation, and, with respect to any criminal action or proceeding, had no reasonable cause to believe that the person's conduct was unlawful. Section 145 of the DGCL further provides that a corporation similarly may indemnify any person who was or is a party or is threatened to be made a party to any threatened, pending or completed action or suit by or in the right of the corporation to procure a judgment in its favor by reason of the fact that the person is or was a director, officer, employee or agent of the corporation, or is or was serving at the request of the corporation as a director, officer, employee or agent of another corporation, partnership, joint venture, trust or other enterprise against expenses (including attorneys' fees) actually and reasonably incurred by the person in connection with the defense or settlement of such action or suit if the person acted in good faith and in a manner that the person reasonably believed to be in or not opposed to the best interests of the corporation and except that no indemnification shall be made in respect of any claim, issue or matter as to which such person shall have been adjudged to be liable to the corporation unless and only to the extent that the Delaware Court of Chancery or such other court in which such action or suit was brought shall determine upon application that, despite the adjudication of liability but in view of all of the circumstances of the case, such person is fairly and reasonably entitled to

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indemnity for such expenses which the Delaware Court of Chancery or such other court shall deem proper.

        Section 145 of the DGCL also provides that a corporation has the power to purchase and maintain insurance on behalf of any person who is or was a director, officer, employee or agent of the corporation, or is or was serving at the request of the corporation as a director, officer, employee or agent of another corporation, partnership, joint venture, trust or other enterprise against any liability asserted against such person and incurred by such person in any such capacity, or arising out of such person's status as such, whether or not the corporation would have the power to indemnify such person against such liability under this section.

Certificate of Incorporation

        The Restated Certificate of Incorporation of PCA provides that to the fullest extent permitted from time to time by the DGCL, a director of PCA shall not be liable to the company or its stockholders for monetary damages for a breach of fiduciary duty as a director.

By-laws

        The Second Amended and Restated By-laws of PCA provides that PCA shall indemnify its directors and officers to the maximum extent permitted from time to time by the DGCL.

Insurance

        Our directors and officers are covered under directors' and officers' liability insurance policies maintained by us.

Item 16.    Exhibits.

        Reference is made to the attached Exhibit Index.

Item 17.    Undertakings.

(a)
The undersigned registrant hereby undertakes:

(1)
To file, during any period in which offers or sales are being made, a post-effective amendment to this registration statement:

(i)
To include any prospectus required by Section 10(a)(3) of the Securities Act of 1933;

(ii)
To reflect in the prospectus any facts or events arising after the effective date of the registration statement (or the most recent post-effective amendment thereof) which, individually or in the aggregate, represent a fundamental change in the information set forth in the registration statement. Notwithstanding the foregoing, any increase or decrease in volume of securities offered (if the total dollar value of securities offered would not exceed that which was registered) and any deviation from the low or high end of the estimated maximum offering range may be reflected in the form of prospectus filed with the Commission pursuant to Rule 424(b) if, in the aggregate, the changes in volume and price represent no more than a 20% change in the maximum aggregate offering price set forth in the "Calculation of Registration Fee" table in the effective registration statement;

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(b)
The undersigned registrant hereby undertakes that, for purposes of determining any liability under the Securities Act of 1933, each filing of the registrant's annual report pursuant to Section 13(a) or Section 15(d) of the Securities Exchange Act of 1934 (and, where applicable, each filing of an employee benefit plan's annual report pursuant to Section 15(d) of the Securities Exchange Act of 1934) that is incorporated by reference in the registration statement shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

(c)
Insofar as indemnification for liabilities arising under the Securities Act of 1933 may be permitted to directors, officers and controlling persons of the registrant pursuant to the provisions referred to in Item 15, or otherwise, the registrant has been advised that in the opinion of the Securities and Exchange Commission such indemnification is against public policy as expressed in the Act and is, therefore, unenforceable. In the event that a claim for indemnification against such liabilities (other than the payment by the registrant of expenses incurred or paid by a director, officer or controlling person of the registrant in the successful defense of any action, suit or proceeding) is asserted by such director, officer or controlling person in connection with the securities being registered, the registrant will, unless in the opinion of its counsel the matter has been settled by controlling precedent, submit to a court of appropriate jurisdiction the question whether such indemnification by it is against public policy as expressed in the Act and will be governed by the final adjudication of such issue.

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SIGNATURES

        Pursuant to the requirements of the Securities Act of 1933, the registrant certifies that is has reasonable grounds to believe that it meets all of the requirements for filing on Form S-3 and has duly caused this Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Lake Forest, State of Illinois on the 4th day of March, 2008.

    PACKAGING CORPORATION OF AMERICA

 
 
By:
 
/s/ PAUL T. STECKO
    Name:   Paul T. Stecko
    Title:   Chairman of the Board and Chief Executive Officer


POWER OF ATTORNEY

        KNOW ALL MEN BY THESE PRESENTS that each person whose signature appears below constitutes and appoints Paul T. Stecko, Richard B. West and Kent A. Pflederer, and each of them, his true and lawful attorneys-in-fact and agents, with full power of substitution and resubstitution, for him and in his name, place and stead, in any and all capacities, to execute any and all amendments and supplements to this registration statement and any subsequent registration statement filed pursuant to Rule 462(b) under the Securities Act of 1933, as amended, and to file the same, with all exhibits thereto, and other documents in connection therewith, with the Securities and Exchange Commission, granting unto said attorneys-in-fact and agents, and each of them, full power and authority to do and perform each and every act and thing requisite and necessary to be done in and about the premises, as fully to all intents and purposes as he might or could do in person, hereby ratifying and confirming all that said attorneys-in-fact and agents or any of them, or their, or his substitute or substitutes, may lawfully do or cause to be done by virtue hereof.

        Pursuant to the requirements of the Securities Act of 1933, this Registration Statement and power of attorney have been signed by the following persons in the capacities indicated on the 4th day of March, 2008.

Signature
   Title

 
 
 
/s/ PAUL T. STECKO
Paul T. Stecko		   Chairman of the Board and Chief Executive Officer (Principal Executive Officer)

/s/ RICHARD B. WEST
Richard B. West
 
Senior Vice President and Chief Financial Officer (Principal Financial and Accounting Officer)

/s/ HENRY F. FRIGON
Henry F. Frigon
 
Director

/s/ LOUIS A. HOLLAND
Louis A. Holland
 
Director


/s/ SAMUEL M. MENCOFF
Samuel M. Mencoff
 
Director

/s/ ROGER B. PORTER
Roger B. Porter
 
Director

/s/ RAYFORD K. WILLIAMSON
Rayford K. Williamson
 
Director


EXHIBIT INDEX

Exhibit No.
   Description
1.1   Form of Underwriting Agreement for Debt Securities (1)

4.1
 
Indenture between PCA and U.S. Bank National Association, as trustee, dated as of July 21, 2003 (2)

4.2
 
First Supplemental Indenture between PCA and U.S. Bank National Association, as trustee, dated as of July 21, 2003 (3)

4.3
 
Form of Debt Securities (1)

5
 
Opinion of Kirkland & Ellis LLP

12
 
Statement regarding computation of ratio of earnings to fixed charges

23.1
 
Consent of Ernst & Young LLP

23.2
 
Consent of Kirkland & Ellis LLP (set forth in Exhibit 5)

24
 
Powers of attorney (included on the signature page of the Registration Statement)

25
 
Form T-1 Statement of Eligibility Under the Trust Indenture Act of 1939 of U.S. Bank National Association, as trustee
(1)
To be filed, if necessary, by a post-effective amendment to the registration statement or as an exhibit to a document incorporated by reference herein.

(2)
Incorporated by reference to Exhibit 4.2 of PCA's Quarterly Report on Form 10-Q filed with the SEC on August 13, 2003.

(3)
Incorporated by reference to Exhibit 4.3 of PCA's Quarterly Report on Form 10-Q filed with the SEC on August 13, 2003.



QuickLinks

TABLE OF CONTENTS
ABOUT THIS PROSPECTUS
OUR COMPANY
RISK FACTORS
FORWARD-LOOKING STATEMENTS
USE OF PROCEEDS
RATIO OF EARNINGS TO FIXED CHARGES
DESCRIPTION OF DEBT SECURITIES
PLAN OF DISTRIBUTION
LEGAL MATTERS
EXPERTS
WHERE YOU CAN FIND MORE INFORMATION
INCORPORATION OF CERTAIN INFORMATION BY REFERENCE
PART II INFORMATION NOT REQUIRED IN PROSPECTUS
SIGNATURES
POWER OF ATTORNEY
EXHIBIT INDEX