As a part of the Army of the Potomac, it was initially assigned to the defenses of Washington, D.C. Later, the 68th was transferred to the Shenandoah Valley and fought at the Battle of Cross Keys. The men of the 68th were then reassigned to central Virginia and found themselves in the thick of the fighting at Second Bull Run. After returning to the nation's capital, the regiment fought in Chancellorsville and was routed by Confederate forces. At Gettysburg, they saw battle on two of the three days and took heavy losses.