United States. Army. District of Vicksburg.

Born in rural Onondaga County, N.Y., Henry Warner Slocum attended Cazenovia Seminary and worked as a teacher before obtaining an appointment to the United States Military Academy at West Point, where he was the roommate of Philip Sheridan. At the outbreak of the Civil War, Slocum was appointed colonel of the 27th New York Infantry, which was a two-year regiment mustered in at Elmira, New York. In 1862, Slocum was appointed major general of volunteers, the second youngest man in the Army to achieve that rank. Later he he assumed command of the XII Corps after its commander, Maj. Gen. Joseph K. Mansfield, was killed at the Battle of Antietam.