Bighorn Canyon National Recreation Area, established by Congress on October 15, 1966, spans 120,296.22 acres on the Montana-Wyoming border around the Bighorn River canyon and the reservoir formed by Yellowtail Dam. Its landscape holds a far older human story, with evidence of people in the area 12,000 years ago, the Bad Pass trail as a seasonal route, and the region’s later importance in Crow country. The recreation area grew from a contested federal dam project that transformed the river into Bighorn Lake. Today it is valued for boating, fishing, camping, wildlife habitat, ranching history, and other outdoor recreation across its two unconnected districts.