Fort Abraham Lincoln log scouts' quarters. Water was supplied to the fort by being hauled from Missouri River in wagons, while wood was supplied by contract. By 1873, the 7th Cavalry moved into the fort to ensure the expansion of the Northern Pacific Railway. The first post commander of the expanded fort was Lieutenant Colonel George A. Custer, who held the position until his death in 1876. In 1876, the Army departed from here as part of the Great Sioux War of 1876-77, resulting in Custer's defeat at the Battle of the Little Bighorn, where they were to push the non-treaty Indians back
Sioux Great Sioux War of 1876. It took place on June 25–26, 1876, along the Little Bighorn River in the Crow Indian Reservation in southeastern Montana Territory. The fight was an overwhelming victory for the Lakota, Northern Cheyenne, and Arapaho, who were led by several major war leaders, including Crazy Horse and Chief Gall, and had been inspired by the visions of Sitting Bull ("Tȟatȟáŋka Íyotake"). The US 7th Cavalry, a force of 700 men, suffered a major defeat while under the command of Lieutenant Colonel George Armstrong Custer (formerly a brevetted major general during the American Civil War). Five of