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.
2nd Cavalry Regiment (United States) and was spread out, often with only one troop occupying a post. In December 1866, 25 troopers of the 2nd Cavalry under LT George W. Grummond accompanied CPT William J. Fetterman in his expedition against Chief Red Cloud. In northern Wyoming, these 81 men were engaged by a force of roughly 1,000 Indians, where they were all massacred in a desperate battle. On 29 June 1867, a small party of 10 troopers and 1 Indian scout under LT Lyman Kidder were ordered to take dispatches from General William Sherman to LTC George A. Custer. Custer grew impatient and moved out