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
Great Sioux War of 1876 actually been a village of Northern Cheyenne (led by Old Bear, Two Moons and White Bull) with a few Oglala (led by He Dog.) In the late spring of 1876 a second, much larger campaign was launched. From Fort Abraham Lincoln marched the Dakota Column, commanded by General Alfred Terry, with 15 companies or about 570 men, including Custer and all 12 companies of the Seventh Cavalry. The Montana Column, commanded by Colonel John Gibbon, departed Fort Ellis. General Crook commanded a third column that departed Fort Fetterman to head north. The plan was for all three columns to converge