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
Henry Armstrong Reed Custer. Heavily influenced by his military uncles, he followed in their footsteps and left Monroe in May 1876, with his sister Emma, for Fort Abraham Lincoln in the Dakota Territory. There, he was hired on May 10 to serve as a beef herder for the 7th Cavalry Regiment, which was under the command of George Armstrong Custer. Reed joined the 7th Cavalry Regiment shortly after the start of the Great Sioux War of 1876–77 in the Montana Territory, part of the larger American Indian Wars. While Reed was never officially enlisted as a soldier, he volunteered his services as such