 In August and September, 1876, He was sent with the Eleventh Infantry from the Department of Texas to the Department of Dakota for field service in connection with the Great Sioux War of 1876-77 in the Dakota Territory and in Montana.Captain Schwan served at Cheyenne River Agency, D.T., Fort Custer, M.T., Fort Bennett, D.T., and Fort Sully, D.T., 1876–80.On May 16, 1877, Lt. Gen. Sheridan directed his brother Lt. Col. Michael V. Sheridan to retrieve the bodies of Custer and his officers.