The forts were almost all built on private land taken by the Army at the start of the war. Most of the owners never recovered the income they lost during the four years of military occupation. Records from the building of Fort Slemmer note that the 24-acre plot belonged to Henry Douglas, a florist; the Army destroyed his flowers, his 1,970 fruit trees, his vines and bushes - the working stock of his trade - to clear ground for the earthworks. The land for Forts Chaplin and Craven was seized from Selby B. Scaggs, a Maryland farmer who owned 400 acres worth $52,000. The 1860 Census Slave Schedule recorded that Scaggs enslaved sixteen people on that land. Fort Stevens itself stood partly on land owned by the Emory Methodist Church and partly, according to longstanding local accounts, on land owned by Elizabeth Thomas, a free Black woman whose house was demolished to make way for the parapet. Documentation of Thomas's ownership was never recovered, but her story is part of the local memory of the site.

The forts were not meant to last. They were earthen embankments revetted with timber, surrounded by trenches, fronted by abatis - sharpened tree branches projecting outward as anti-personnel barriers. Only the largest had any masonry. The Army was clear from the start that the land would be returned to its owners after the war and the works would be dismantled. That happened quickly. Most of the 68 forts were abandoned in 1865 and 1866. The earthworks slumped, the timber rotted, and the trenches filled with leaves and silt. The land, often along ridges that commanded views of the river approaches, sometimes became farmland again and sometimes was subdivided into the suburban neighborhoods that pushed out from the old city limits in the late nineteenth century. A few sites were never fully cleared. Their grass-covered profiles still trace polygonal patterns on the hilltops where artillery once pointed outward.

In 1898 someone proposed connecting the surviving fort sites by a parkway. The idea kept coming back. In 1919 the District Commissioners pushed Congress to consolidate the old forts into a Fort Circle - a green ring of parks outside the city, owned by the federal government and linked by a Fort Drive that would let Washingtonians escape into countryside that was disappearing fast. The 1919 bill failed. A 1925 version passed, creating the National Capital Parks Commission and authorizing the slow purchase of fort land back from private owners. Fort Stanton was bought in 1926 for $56,000. Through the 1930s the Civilian Conservation Corps trimmed trees, cleared brush, and built structures at the parks. World War II interrupted construction. Postwar budget cuts under Truman delayed the Fort Drive again. By 1963, when Kennedy briefly pushed Congress to finally build the ring road, Washington had simply grown past it, and the surface streets already connected the parks in their own way. The Fort Drive was quietly dropped and replaced by a hiking trail.

Today the forts are scattered across three National Park Service units. National Capital Parks-East administers Fort Foote, Fort Greble, Fort Stanton, Fort Ricketts, Fort Davis, Fort DuPont, Fort Chaplin, Fort Mahan, and Battery Carroll. Rock Creek Park administers Fort Bunker Hill, Fort Totten, Fort Slocum, Fort Stevens, Fort DeRussy, Fort Reno, Fort Bayard, Battery Kemble, and Battleground National Cemetery - the small cemetery where the 41 Union soldiers killed defending Fort Stevens are buried. Fort Marcy across the Potomac in Virginia is administered by the George Washington Memorial Parkway unit. A 19.5-mile trail connecting many of the sites was designated a National Recreation Trail in 1971. In 2024 legislation was proposed to combine the forts into a single national historical park; the Park Service opposed the change, preferring the existing distributed administration.

What you actually see at the surviving sites varies. At Fort Stevens, the parapet has been partially reconstructed and a marker indicates where Lincoln stood under fire. At Fort Reno, the highest natural point in Washington at about 409 feet, the earthworks are mostly gone but the park retains the open ground that once held a 20-acre fortification, 50 more acres of barracks, and the headquarters of multiple commands. At Fort DeRussy, deep inside Rock Creek Park, the magazine bunker is partially visible beneath thick woods. The earthworks are easy to miss if you don't know what you're looking at. Many of them survive as low grassy ridges threading through neighborhoods that grew up around the forts after the war. They are the trace of the country's first modern siege defense, built in a hurry and torn down almost as quickly, recoverable now only because the land was eventually pulled back from private hands and made into a ring of parks - even if the road that was supposed to connect them never got built.