The Gun Lake Trust Land Reaffirmation Act (S. 1603) is an act of Congress that reaffirmed the status of lands taken into trust by the Department of the Interior (DOI) for the benefit of the Match-E-Be-Nash-She-Wish Band of Pottawatomi Indians in the state of Michigan. The bill was introduced and passed during the 113th United States Congress and became federal law on September 26, 2014 when signed by President Barack Obama. In 2018, the Supreme Court of the United States affirmed the law's constitutionality in Patchak v. Zinke.