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 sheep both indicated on Clark's map and did retain their names, the latter being the namesake of the Battle of the Little Bighorn. Bighorn sheep The bighorn sheep ("Ovis canadensis") is a species of sheep native to North America named for its large horns. These horns can weigh up to , while the sheep themselves weigh up to . Recent genetic testing indicates three distinct subspecies of "Ovis canadensis", one of which is endangered: "O. c. sierrae". Sheep originally crossed to North America over the Bering land bridge from Siberia; the population in North America peaked in the millions, and the