The 123rd Pennsylvania Infantry Regiment lost 3 officers and 27 enlisted men killed or mortally wounded and 1 officer and 41 enlisted men to disease during the Civil War.

August Organized at Allegheny City for nine months service
August 20-23 Moved to Harrisburg, Pa., then to Washington, D.C. Attached to 2nd Brigade, 3rd Division, 5th Army Corps, Army of the Potomac.
September 6-24 Maryland Campaign
October Duty at Sharpsburg, Md.
October 30-November 19 Movement to Falmouth, Va.
December 12-15 Battle of Fredericksburg, Va.
January 20-24 Burnside’s 2nd Campaign, “Mud March”
January-April Duty at Falmouth
April 27-May 6 Chancellorsville Campaign
May 1-5 Battle of Chancellorsville

The regiment elected to stay on past the expiration of its enliistement until the battle was done.

May 13 Mustered out