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 of the Potomac reorganized under the command of Major General Philip Sheridan, Custer (now commanding the 3rd Division) led his "Wolverines" to the Shenandoah Valley where by the year's end they defeated the army of Confederate Lieutenant General Jubal Early in the Valley Campaigns of 1864. During May and June, Sheridan and Custer (Captain, 5th Cavalry, May 8 and Brevet Lieutenant Colonel, May 11) took part in cavalry actions supporting the Overland Campaign, including the Battle of the Wilderness (after which Custer ascended to division command), and the Battle of Yellow Tavern (where J.E.B. Stuart was mortally wounded). In the