SEC Form 4

FORM 4		UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940	OMB APPROVAL OMB Number: 3235-0287 Estimated average burden hours per response: 0.5
	Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person* MENCOFF SAMUEL M (Last) (First) (Middle) THREE FIRST NATIONAL PLAZA SUITE 3800 (Street) CHICAGO IL 60602 (City) (State) (Zip)	2. Issuer Name and Ticker or Trading Symbol PACKAGING CORP OF AMERICA [ PKG ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X Director X 10% Owner Officer (give title below) Other (specify below)
	3. Date of Earliest Transaction (Month/Day/Year) 10/20/2006
	4. If Amendment, Date of Original Filed (Month/Day/Year)	6. Individual or Joint/Group Filing (Check Applicable Line) X Form filed by One Reporting Person Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock, $0.01 par value	10/20/2006		J(1)		942,434	D	$0	16,733,010	I	Through PCA Holdings LLC(2)(3)
Common Stock, $0.01 par value	10/20/2006		J(4)		4,466	A	$0	4,466	I	Through Madison Dearborn Partners, LLC(2)(5)
Common Stock, $0.01 par value	10/20/2006		J(6)		6,685	A	$0	6,685	I	Through Emily Case Mencoff - Dynasty Trust(2)(7)
Common Stock, $0.01 par value	10/20/2006		J(8)		6,685	A	$0	6,685	I	Through Samuel Keefer Mencoff - Dynasty Trust(2)(7)
Common Stock, $0.01 par value	10/20/2006		J(9)		6,685	A	$0	6,685	I	Through George Grove Mencoff - Dynasty Trust(2)(7)
Common Stock, $.01 par value	10/20/2006		J(10)		63,445	A	$0	63,445	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

1. Reflects the continuation of a pro rata distribution of shares of common stock of the issuer by Madison Dearborn Partners III, L.P. ("MDP III"), the record and direct beneficial owner of the shares, to its partners, including Madison Dearborn Partners, LLC ("MDP LLC"), the sole general partner of MDP III, on October 20, 2006. The pro rata distribution was commenced by PCA Holdings LLC ("Holdings") on September 6, 2006, as previously reported by the reporting person.

2. The reporting person expressly disclaims beneficial ownership of 16,757,531 shares reported in Table I as indirectly beneficially owned, except to the extent of his pecuniary interest therein, and the inclusion of these shares in this report shall not be deemed an admission of beneficial ownership of these shares for purposes of Section 16 or for any other purpose.

3. Holdings is the record and direct beneficial owner of 16,733,010 shares. The shares held by Holdings may be deemed to be beneficially owned by Madison Dearborn Capital Partners III, L.P. ("MDCP III"), the managing member of Holdings, a fund affiliated with MDCP III, MDP III, the sole general partner of MDCP III and the fund affiliated with MDCP III, and MDP LLC. The reporting person is a managing director and member of MDP LLC and may be deemed to have an indirect pecuniary interest in the shares owned by Holdings to the extent of the reporting person's indirect proportionate interest in Holdings.

4. Consists of shares of common stock of the issuer received by MDP LLC as a result of the distribution by MDP III to its partners.

5. MDP LLC is the record and direct beneficial owner of 4,466 shares received by MDP LLC as a result of the distribution by MDP III to its partners. The reporting person is a managing director and member of MDP LLC and may be deemed to have an indirect pecuniary interest in the shares owned by MDP LLC to the extent of the reporting person's proportionate interest in MDP LLC.

6. Consists of shares of common stock of the issuer received by Emily Case Mencoff - Dynasty Trust as a result of the distribution by MDP III to its partners.

7. Each of the Emily Case Mencoff - Dynasty Trust, Samuel Keefer Mencoff - Dynasty Trust and George Grove Mencoff - Dynasty Trust (collectively, the "Trusts") is the record and direct beneficial owner of 6,685 shares received as a result of the distribution by MDP III to its partners. These shares are held in trust for the benefit of the reporting person's children. The reporting person's spouse is a trustee of the Trusts.

8. Consists of shares of common stock of the issuer received by Samuel Keefer Mencoff - Dynasty Trust as a result of the distribution by MDP III to its partners.

9. Consists of shares of common stock of the issuer received by George Grove Mencoff - Dynasty Trust as a result of the distribution by MDP III to its partners.

10. Consists of shares of common stock of the issuer received by the reporting person as a result of the distribution by MDP III to its partners.

	/s/ SAMUEL M. MENCOFF	10/24/2006
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
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