By 
Fort Slocum in Washington DC - managed by the National Park Service
Here’s an oasis of green you don’t see often in the middle of a city: Fort Slocum Park, where a cool urban forest abuts the row houses of Northwest DC.
Nestled in northern Petworth, you’ll first notice Fort Slocum by the green hill you see on Kansas Avenue NW, the only remnant of the Civil War earthworks that defended Washington DC from Confederate General Jubal A. Early’s attack in June 1864.
While the National Park Service description is brief, the Historic Marker Database tells the full story:
When the Confederates demonstrated against Fort Stevens, to the west, Fort Slocum had the honor of opening the engagement by firing its long range guns. During the battle, some 1,500 employees of the Army Quartermaster office, led by General Montgomery Meigs, assisted the fort’s garrison.
Juxtaposed to that history is a modern escape for all manner of Washingtonians, as I found on a recent exploration of its central woods..