The CIPZIP Act of 2025 directs the U.S. Postal Service to create a formal process allowing state, local, and Tribal governments to request changes to ZIP code boundaries or the creation of new ZIP codes. Within 180 days of enactment, the Postal Service must establish public criteria for reviewing these requests, considering factors like operational impact, costs, and future address needs, while designating a specific contact person for applicants and providing written explanations for any denials. Governments whose requests are denied can appeal once within 45 days, generally cannot resubmit the same request for five years, but those denied in the past decade get a one-time chance to reapply regardless of similarity to prior requests. The bill also establishes a seven-year pilot program letting local governments help cover Postal Service costs tied to approved boundary changes through funding or in-kind agreements, with denials based purely on cost required to include a cost estimate and a 30-day window to propose a cost-sharing deal. The Postal Regulatory Commission must report annually to Congress on how the pilot program is used, and the Postal Service must respond to individual lawmakers' inquiries about specific denials, though the bill clarifies it does not otherwise limit the Postal Service's existing authority over mail operations.