with the 5th U.S. Volunteer Infantry, he was in an Indian skirmish near Ellsworth Kansas, and was mustered out of service with "volunteer" forces, again, on August 10, at Fort Leavenworth, Kansas. From civilian life McDougall was offered a commission as second lieutenant, 14th US Infantry, May 10, 1866. He accepted the commission on July 21, 1866, at Fort Laramie. On September 21, 1866, he was transferred to the 32nd US Infantry and received promotion to first lieutenant to rank from January 14, 1867. After a brief service at Fort Vancouver and Fort Walla Walla, Washington, McDougall went to Arizona in 1867, and engaged in scouting and had fights with various bands and groups of Apache Indians at Aravipa Canyon, Tonto Basin, Point of Mountain and Rock Springs, Arizona. During the reorganization of the Army he was transferred to the 21st US Infantry on April 19, 1869, and was unassigned on October 21, 1869. He was assigned to the 7th US Cavalry on December 30, 1870, and was stationed in South Carolina during the Ku Klux Klan troubles in that state. He married Alice M. Sheldon on May 21, 1872, in Spartanburg, SC. After the 7th Cavalry was reassembled at Fort Abraham Lincoln, he was engaged with Sioux at the mouth of the Big Horn River, Montana August 11, 1873, when accompanying the David Stanley Yellowstone Expedition. He also was on Custer's 1874 Black Hills Expedition, Commanding Company E. Charged with being drunk on duty, he was acquitted during a court-martial in March 1875 and subsequently he was appointed captain on December 15, 1875. Battle of the Little Bighorn In 1876 Captain McDougall commanded Company B of 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. Before the battle – The Dakota Column 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. The twelve companies of the 7th Cavalry Regiment, commanded by Lt. Col. Custer, were the main combat element of a larger column of soldiers, called the Dakota Column commanded by General Alfred Terry.