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
Little Bighorn River led a government expedition up the Big Horn River to the mouth of Big Horn Canyon, and then southeast along the base of the Big Horn mountains. En route to the Big Horn Canyon, and about 40 miles down the Big Horn River, he camped just below the mouth of the Little Bighorn on September 6, 1859. He noted in his journal for that day that the Indian name of the Big Horn river, into which the Little Bighorn empties, is "Ets-pot-agie", or Mountain Sheep River, and this generates the name of the Little Big Horn, "Ets-pot-agie-cate", or Little Mountain