Cannon of largest size (200 lb gun) mounted in Fort, Battery Rodgers, on Morris Island. 

Battery Rodgers was a gun emplacement that composed a portion of the American Civil War defenses of the American capital city of Washington, D.C.  Built in 1863, Battery Rodgers was constructed with the ability to interdict sea traffic sailing up the Potomac River to Washington. From its position on a 28-foot high cliff overlooking Battery Cove, it was positioned with a clear view of fire and was ably suited to guarding the southern Potomac River and Accotink Road (Fort Hunt Rd.) approaches to Washington. 

During the war, the battery mounted one 6.4 inch (100 pounder) Parrott rifle and one 15-inch Rodman Gun, one of the largest guns in the world at that time. The guns were supplied by two adjacent powder magazines, and the battery complex included a hospital, barracks, mess hall, and prison.

It was garrisoned by 6 commissioned officers, 1 ordnance sergeant, and 256 men.