The I Corps remained in northern Virginia instead of following the rest of the Army for the Peninsula Campaign in 1862.

At the Battle of Fredericksburg on December 13, the 3rd formed part of the force which briefly broke through the Confederate right.

After Fredericksburg, the 3rd was assigned to the XXII Corps defending Washington, where it rested and recruited members.

In January 1864, it was sent, along with the 4th Reserves, to West Virginia, where it performed garrison duty and fought at the Battle of Cloyd's Mountain.

Men who reenlisted and those whose enlistments had not yet expired were transferred to the 54th Pennsylvania Volunteer Infantry on June 8, 1864.