The largest surrender of United States forces during the Civil War took place at Harpers Ferry

The Battle of Harpers Ferry started with light fighting September 13 as the Confederates tried to capture the Maryland Heights to the northeast, while John Walker moved back over the Potomac to capture Loudoun Heights south of town. The surrender at Harpers Ferry was the largest surrender of U.S. military personnel until the Battle of Bataan in World War II, despite the fact that the number of dead and injured soldiers was relatively low afterwards. The almost 12,400 Union soldiers stationed at the fortress became Confederate prisoners after the Federal garrison capitulated on September 15, 1862.

Many of these captives were marched to Camp Parole near Annapolis after Gen. A.P. Hill granted them parole in order to be exchanged for Confederate prisoners.