Civil War Defenses of Washington

Civil War Fort Sites
U.S. National Register of Historic Places
Union Army soldiers with the 3rd Massachusetts Heavy Artillery Regiment at Fort Totten in Washington, D.C. in August 1865
Location	Washington, D.C. Fairfax County, Virginia Prince George's County, Maryland
NRHP reference No.	74000274 (original) 78003439 (increase)
Significant dates
Added to NRHP	July 15, 1974[1]
Boundary increase	September 13, 1978

The Civil War Defenses of Washington were a group of Union Army fortifications that protected the federal capital city, Washington, D.C., from invasion by the Confederate States Army during the American Civil War.

Some of these fortifications are part of a grouping of properties now managed by the National Park Service (NPS) and listed on the National Register of Historic Places. Others are parts of state, county, or city parks or are located on privately owned properties. A trail connecting the sites is part of the Potomac Heritage Trail.

Parts of the earthworks of some such fortifications still exist; others have been demolished.