| Fort Thayer | |
|---|---|
| Part of the Civil War defenses of Washington, D.C. | |
| Washington, D.C. | |
 Fort Thayer on a map of 1863 | |
  Fort Thayer | |
| Coordinates | 38°55′43.81″N 76°58′18.03″W / 38.9288361°N 76.9716750°W[1] |
| Type | Earthwork fort |
| Site information | |
| Controlled by | Union Army |
| Condition | Residential Area |
| Site history | |
| Built | 1861 |
| In use | 1861–1865 |
| Materials | Earth and timber |
| Demolished | 1865 |
| Battles/wars | American Civil War |
Fort Thayer was one of seven temporary earthwork forts part of the Civil War Defenses of Washington, D.C., during the Civil War built in the Northeast quadrant of the city at the beginning of the Civil War by the Union Army to protect the city from the Confederate Army. From west to east, the forts were as follow: Fort Slocum, Fort Totten, Fort Slemmer, Fort Bunker Hill, Fort Saratoga, Fort Thayer and Fort Lincoln. Unlike other forts, today nothing remains of the structure.