Hot Springs State Park in Thermopolis, Wyoming, developed around mineral hot springs that emerge at a constant 135 °F and supply the State Bath House, where the water is cooled for free public bathing. The park began after an 1896 federal purchase of part of the Eastern Shoshone reservation, with a 1-square-mile section transferred to Wyoming in 1897 as the state’s first state park. Mineral-rich waters built distinctive travertine terraces, and the grounds include gardens, a suspension footbridge, picnic shelters, boat docks, and nearby Legend Rock. A small bison herd introduced in 1916 remains there as the State Bison Herd.