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.
7th Iowa Volunteer Cavalry Regiment the Battle of Killdeer Mountain and in the Battle of the Badlands. Units of the regiment were at Camp Rankin on the South Platte in January, 1865 when more than 1,000 plains Indians attacked the fort and stage station at Julesburg during the Sioux Wars following the Sand Creek Massacre. In the Battle of Julesburg, 14 men of the 7th were killed, including 4 non-commissioned officers. Company F of the regiment accompanied Colonel James H. Kidd's column of the Powder River Expedition in 1865 to the Powder and Tongue river valley's in Dakota Territory and Montana Territory. The regiment was