The 102nd Pennsylvania Infantry was organized at Pittsburgh, Pennsylvania in August 1861 and mustered in for a three-year enlistment under the command of Colonel Thomas Algeo Rowley.

The regiment was attached to Peck's Brigade, Couch's Division, Army of the Potomac, October 1861 to March, 1862.

3rd Brigade, 1st Division, IV Corps, Army of the Potomac, to July 1862.

2nd Brigade, 1st Division, IV Corps, Army of the Potomac, to September, 1862.

2nd Brigade, 3rd Division, VI Corps, Army of the Potomac, to October 1862.

3rd Brigade, 3rd Division, VI Corps, to January 1864.

Wheaton's Brigade, Department of West Virginia, to March 1864.

The 102nd Pennsylvania Infantry mustered out of service June 28, 1865.

Five companies left Pennsylvania for Washington, D.C., August 21, 1861.

Battle of Fair Oaks, Seven Pines, May 31 – June 1.

Covered Pope's retreat to Fairfax Court House August 30 – September 1.

Movement to Stafford Court House October 20 – November 18, and to Belle Plains December 5.

Burnside's 2nd Campaign, "Mud March," January 20–24, 1863.

Pursuit of Early to Snicker's Gap July 14–18, Sheridan's Shenandoah Valley Campaign August to December.

Demonstration on Gilbert's Ford, Opequan Creek, September 13.