The 10th Pennsylvania Reserves was organized at Camp Wilkins near Pittsburgh, Pennsylvania beginning June 3, 1861 and mustered on July 21, 1861 under the command of Colonel John S. McCalmont.
The regiment was attached to 3rd Brigade, McCall's Pennsylvania Reserves Division, Army of the Potomac, to March 1862.
3rd Brigade, 2nd Division, I Corps, Army of the Potomac, to April 1862.
3rd Brigade, McCall's Division, Department of the Rappahannock, to June 1862.
3rd Brigade, 3rd Division, V Corps, Army of the Potomac, to August 1862.
3rd Brigade, 3rd Division, III Corps, Army of Virginia, to September 1862.
3rd Brigade, 3rd Division, I Corps, Army of the Potomac, to February 1863.
3rd Brigade, Pennsylvania Reserves Division, XXII Corps, Department of Washington, to June 1863.
3rd Brigade, 3rd Division, V Corps, Army of the Potomac, to June 1864.
At Tennallytown, Md., August 1 to October 10, 1861, and at Camp Pierpont, near Langley, Va., until March 1862.