Fort Dupont was commenced between Ocotober and December of 1861, and "completed" in the spring of 1862. Like most of the older works it underwent some modifications between 1861 and 1865. In the line concept of fortications over the Anacostia River, it functioned to cover the gap in the fortified ridge between Forts Mahan and Miegs.
It was never a strong work and in 1862, a commission studying the Defenses of Washington noted that a deep ravine to the west of the fort should be covered by a blockhouse. At other times, traverses to cover the sally port, magazine and rifle pits to the cover approaches were recommended.
In April 1864, General Bayard advised the abandonment of Fort Dupont, and in 1865 the fort was closed and site reverted to its original landowner, Michael Caton. Fort Dupont had six sides, each 100 feet long, protected by a deep moat and trees felled side-by-side with branches pointing outward. It was named for Flag Officer Samuel F. Dupont, who commanded the naval victory at Port Royal, South Carolina, in November 1861.
Although its garrison and guns never saw battle, Fort Dupont served as a lifeline of freedom. Runaway slaves found safety here before moving on to join the growing community of "contrabands" in Washington. The barracks and guns are gone, but the fort's earthworks can still be traced near the picnic area on Alabama Avenue.
In the 1930s, the National Capital Planning Commission acquired the old fort and surrounding land for recreation. A golf course was constructed and as the city grew, golf gave way in 1970 to the sports complex along Ely Place that now includes tennis and basketball courts, athletic fields, a softball diamond, and an indoor ice rink. Once where soldiers viewed farmlands, park visitors now grow fruits and vegetables in the community garden.