The Pryor Mountains Wild Horse Range, on the Montana-Wyoming border, was established in 1968 as the first protected refuge in the United States devoted exclusively to mustangs. Created to protect the free-roaming Pryor Mountain herd, it emerged from a national fight over federal horse removals from public land. Plans to remove this herd in the 1960s sparked a public campaign led by Wild Horse Annie and local supporters, and protest intensified after national television coverage. A court order halted trapping, and Interior Secretary Stewart Udall created the range. The herd later gained added importance for its unusual genetics and for its role in the broader wild horse conservation movement.