 The 116th Regiment, Pennsylvania Volunteer Infantry, was recruited from among the Irish Americans of Philadelphia, Pennsylvania, during the summer of 1862.Dennis Heenan served as its first colonel, St. Clair A. Mulholland as lieutenant colonel, and George H. Bardwell as major.At the end of August 1862, the regiment was ordered to report to Washington, D.C., and was assigned to the Irish Brigade, which was the 2nd Brigade,
1st Division, II Corps, Army of the Potomac.