Originally organized as the 116th Pennsylvania Volunteers, the "Irish Dragoons" were to be a squadron of cavalry commanded by Captain James A. Galligher, and attached to the New York-based "Irish Brigade." When President Lincoln issued manpower quotas to the several states, Pennsylvania requested their men be returned in order to help fill the quotas. A full regiment was raised, re-numbered as the 117th Pennsylvania Volunteer Regiment, aka the 13th regiment of Pennsylvania Cavalry. Originally recruited and organized at
Philadelphia and
Harrisburg,
Pennsylvania beginning in December 1861, they were mustered in for three years service under the command of newly promoted
Colonel James A. Galligher. The regiment was attached to Defenses of Baltimore,
VIII Corps,
Middle Department, to September 1862. Defenses Upper Potomac, VIII Corps, to February 1863. Elliott's Brigade, Milroy's Command, Winchester, Virginia, VIII Corps, February 1863. 1st Brigade, 2nd Division, VIII Corps, to July 1863. 3rd Brigade, 2nd Division, Cavalry Corps,
Army of the Potomac, to August 1863. 2nd Brigade, 2nd Division, Cavalry Corps, Army of the Potomac, to February 1865. (Served attached to
IX Corps, Army of the Potomac, May 3–26, 1864.) Terry's Provisional Corps,
Department of North Carolina, to March 1865. 3rd Brigade, Kilpatrick's 3rd Division, Cavalry Corps, Military Division of Mississippi, to July 1865. The 13th Pennsylvania Cavalry mustered out in
Raleigh, North Carolina, on July 14, 1865, and traveled by rail to Philadelphia, Pennsylvania, where they were discharged on July 27, 1865. ==Detailed service==