October 24, 2024 Robert P. Mundy Chief Financial Officer Packaging Corporation of America 1 North Field Court Lake Forest, Illinois 60045 Re: Packaging Corporation of America Form 10-K for the Year Ended December 31, 2023 Filed February 29, 2024 File No. 001-15399 Dear Robert P. Mundy: We have completed our review of your filing. We remind you that the company and its management are responsible for the accuracy and adequacy of their disclosures, notwithstanding any review, comments, action or absence of action by the staff. Sincerely, Division of Corporation Finance Office of Manufacturing