Tags: Military Structure.
Fort Corcoran was a wood-and-earthwork fortification constructed by the Union Army in northern Virginia as part of the defenses of Washington D.C. during the American Civil War. Built in 1861 shortly after the occupation of Arlington Virginia by Union forces it protected the southern end of the Aqueduct Bridge and overlooked the Potomac River and Theodore Roosevelt Island known as *Mason’s Island.*The fort was named after Colonel Michael Corcoran commander of the U.S.
