The "American Battlefield Protection Program Amendments Act of 2026" adjusts grant programs related to battlefield preservation, including reauthorizing a grant program until 2036 and modifying the battlefield interpretation and restoration grant programs. Additionally, the bill mandates the preparation of studies on sites and structures tied to the French and Indian War and the Mexican-American War, assessing their significance and preservation alternatives. The Secretary of the Interior will conduct these studies in consultation with relevant parties and submit a report to Congress within two years.