Thomas Mower McDougall subsequently he was appointed Captain, 15 Dec 1875. In 1876 Captain McDougall commanded Company B and accompanied the 7th Cavalry Regiment, under command of Lt. Col. George A. Custer in its fateful departure from Fort Abraham Lincoln to participate in what became known as the Great Sioux War of 1876, which culminated in the Battle of the Little Bighorn, also known as Custer's Last Stand which occurred on June 25–26, 1876. On May 17, 1876, the 7th Cavalry left their base at Fort Abraham Lincoln near present day Mandan, North Dakota to join in a campaign against the Sioux Indians.
George Armstrong Custer agencies (reservations) or be considered "hostile". At that time the 7th Cavalry's regimental commander, Colonel Samuel D. Sturgis, was on detached duty as the Superintendent of Mounted Recruiting Service and in command of the Cavalry Depot in St. Louis, Missouri, which left Lieutenant Colonel Custer in command of the regiment. Custer and the 7th Cavalry departed from Fort Abraham Lincoln on May 17, 1876, part of a larger army force planning to round up remaining free Indians. Meanwhile, in the spring and summer of 1876, the Hunkpapa Lakota holy man Sitting Bull had called together the largest ever gathering of