General Burnside recommended him for promotion to the rank of major-general U.S.V., which was not however awarded to Humphreys until after Gettysburg.
After General Hooker succeeded Burnside, Butterfield was appointed chief of staff, Army of the Potomac, and in this capacity he served in the Chancellorsville and Gettysburg campaigns.
Early on the 19th the corps of Sumner and Mansfield followed Hooker across the upper stream whilst McClellan's left wing (Burnside's corps) drew up opposite Lee's extreme right.
Burnside, on the southern wing, had received his orders late, and acted on them still later.