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
Little Bighorn River The Lakota Sioux, who began to contest control of this area with the Crow in the 1840s to 1860s as they pushed westward, continued to call the river the "Greasy Grass". Native Americans called the river the Greasy Grass before the Battle of the Little Big Horn in 1876, and Lakota people still commonly refer to the Battle of the Little Bighorn as the Battle of the Greasy Grass. In historical references in Wikipedia articles, the Battle of the Little Bighorn is also referred to as the Battle of the Greasy Grass, as it is in the discussions of the