he regiment was recruited from July to October 1862 with mustering in taking place at Carlisle. It was first assigned to the Army of the Potomac for the 1862 Maryland Campaign skirmishing with Confederates near Hagerstown and participating at Battle of Antietam. It was then transferred to Kentucky where it was remounted and assigned to the Army of the Cumberland in Tennessee and was present at the battles of Stones River and Chickamauga. Among those troopers later honored for gallantry at Stones River were John Tweedale and John Gregory Bourke who were among six men who eventually received the Medal of Honor. For the remainder of the war the 15th remained in the Department of the Cumberland performing garrison duties and occasionally participating in minor skirmishes and raids. It fought in the Knoxville Campaign. In April 1865 the regiment helped capture General Braxton Bragg and his staff and pursued Confederate President Jefferson Davis.