 The fort was named after Colonel Michael Corcoran, commander of the U.S. Fighting 69th Infantry, Irish Brigade 69th New York Volunteer Regiment, one of the units that constructed the fort.Fort Corcoran was home to the Union Army Balloon Corps and the headquarters of the defenses of Washington south of the Potomac River, and served throughout the war before being dismantled in 1866.Today, no trace of the fort remains, although the Arlington County government has erected a historical marker at its site.