On March 1, 1929, the congress of the United States by the passage of an act set out in 45 United States Statutes at Large 1435 revised the boundaries of Yellowstone National Park.
Wyo. Stat. Ann. § 36-10-107
Yellowstone National Park; boundary revision
Official source: Wyoming Legislature. Reproduced from public-domain Wyoming statutes; confirm against the official source for the current text. Not legal advice.