Bighorn River Wind River Canyon near the town of Thermopolis. From there, the river flows through the Bighorn Basin in north central Wyoming, passing through Thermopolis and Hot Springs State Park. At the border with Montana, the river turns northeast, and flows past the north end of the Bighorn Mountains, through the Crow Indian Reservation, where the Yellowtail Dam forms the Bighorn Lake reservoir. The reservoir and the surrounding canyon are part of the Bighorn Canyon National Recreation Area. The Little Bighorn River joins the Bighorn near the town of Hardin, Montana. Approximately fifty miles farther downriver, the Bighorn River ends where
Bighorn Mountains of the Little Bighorn, Tongue, and Powder rivers. Bighorn Canyon National Recreation Area consists of approximately within the Bighorn Mountains. It includes Bighorn Lake, a reservoir damming the Bighorn River. In 2015, a sudden, huge 'gash' was found in Wyoming's Big Horn Mountains. The Wyoming Geological Survey studied the area and determined that "The Crack" may be the result of an "apparent active landslide" in the southern end of the Big Horn Mountains. The Bighorns are a popular destination for hiking, backpacking, fly fishing, horse back riding and increasingly ATV riding and snowmobiling. Trails wind through most of the national