After burying the dead on the field of Second Battle of Bull Run, the regiment was attached to Howe's Brigade of Couch's Division of the IV Corps of the Army of the Potomac where it replaced De Trobriand's 55th New York, Gardes Lafayette regiment on September 11, 1862.

During this time Couch's Division was detached from the Army and was occupied with guarding the fords on the Potomac.

In the Battle of Fredericksburg, it suffered minor casualties from artillery fire, but didn't get a chance to fight.

At the Battle of Gettysburg in July, it helped defend the left flank of the Union army.

In July, it was transferred to Washington, D.C., with the rest of the VI Corps to defeat Lt. Gen. Jubal Early's attack on the city.