The 123rd Pennsylvania Volunteer 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 under Colonel John B. Clark|
|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.|
Battle of Fredericksburg
|January 20-24||Burnside’s 2nd Campaign, “Mud March”|
|January-April||Duty at Falmouth|
|April 27-May 6||Chancellorsville Campaign|
Battle of Chancellorsville
The regiment elected to stay on past the expiration of its enliistement until the battle was done.
|May 13||Mustered out|