Pryor, south of Billings, takes its name from the creek and mountains, which were named by Lewis and Clark for Sgt. Nathaniel Pryor, a member of the expedition. Pryor is on the Crow Indian Reservation and is the site of the Chief Plenty Coups State Park. Plenty Coups, was the last of the great Crow War Chiefs. South of Pryor is the Pryor Mountains Wild Horse Range the first nationally designated area established to provide a home for free roaming wild horses. Today, approximately 120 wild horses roam the area along with bands of bighorn sheep, and mule deer.