History of Montana degree of longitude northward to the boundary line of the British possessions. The boundaries of Montana territory did not change during its existence. Montana was admitted to the Union as the state of Montana on November 8, 1889. The Battle of the Little Bighorn—also called Custer's Last Stand and the Battle of the Greasy Grass—was an armed engagement between a Lakota (Sioux)-Northern Cheyenne-Arapaho combined force and the 7th Cavalry of the United States Army. It occurred June 25–June 26, 1876, near the Little Bighorn River in eastern Montana Territory near present-day Hardin, Montana, on land that today is part of
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