Beginning on January 5, 1865, Chapman led a cavalry division of the Army of the Shenandoah. After the Battle of Waynesboro, Virginia on March 2, he was ordered to remain in the Shenandoah Valley while the rest of the Union forces headed for Petersburg, Virginia. Chapman had with him now three small regiments and a few artillery pieces to hold the Valley. Beginning on April 19, 1865, he was given command of the cavalry division assigned to Washington, D.C. In recognition of his performance at Winchester in September 1864, on January 13, 1866, President Andrew Johnson nominated Chapman for appointment to the grade of brevet major general of volunteers, to rank from March 13, 1865, and the United States Senate confirmed the appointment on March 12, 1866.