|Part of the Civil War defenses of Washington, D.C.|
|Arlington County, Virginia|
Map of Fort Craig and surrounding area including Fort Tillinghast, 1865.
|Controlled by||Union Army|
|Built by||U.S. Army Corps of Engineers|
|Battles/wars||American Civil War|
Fort Tillinghast was a small crescent-shaped, Civil War-era fort built by the Union Army in Arlington County (at that time Alexandria County) in Virginia. It was part of the defensive ring around Washington, D.C. and was occupied throughout the American Civil War. Fort Tillinghast stood about 0.6 miles away from Arlington House, the Union-occupied estate of Confederate General Robert E. Lee.
The fort was part of the Arlington Line and tied into Fort Craig approximately 0.6 miles to the south and Fort Cass approximately 0.3 miles to the north. Along with Forts Cass, Woodbury, Morton, and Strong, Fort Tillinghast was a lunette which covered the approaches to the Aqueduct Bridge (near the modern Key Bridge).
It was named in honor of Captain Otis H. Tillinghast, Quartermaster, killed at the First Battle of Bull Run on July 21, 1861. Oriented to the west, it had a perimeter of 298 yards, emplacements for 12 guns, and 2 magazines as well as a bombproof barracks. The fort's armament included four 24-pound guns, one 24-pound field howitzer, four 30-pound Parrott rifles, two 20-pound Parrott rifles, and two 24-pound Coehorn mortars.
In June, 1865, Fort Tillinghast was ordered dismantled and the site returned to its previous owners. The fort stood near 205 North Wayne Street, Arlington, but no sections remain today. A historic marker, near the intersection of Arlington Boulevard (U.S. 50) and North 2nd Street in Arlington, shows the location where the fort once stood. The marker depicts the fort's position on a map of the city's defenses and reads: Here stood Fort Tillinghast, a lunette in the Arlington Line constructed in August 1861. It had a perimeter of 298 yards and emplacements for 13 guns. A model of this fort, typical of all lunettes in the Arlington Line, can be seen at the Hume School museum of the Arlington Historical Society.
- Cooling III, Benjamin Franklin; Owen II, Walton H. (6 October 2009). Mr. Lincoln's Forts: A Guide to the Civil War Defenses of Washington. Scarecrow Press. pp. 105–107. ISBN 978-0-8108-6307-1.
- War Department, Special Orders No. 315, June 19, 1865; General Orders No.89, HQ, Dept. of Washington, XXII Army Corps, June 23, 1865 (NPS - The Civil War Defenses of Washington)
- The Historical Marker Database - Fort Tillinghast
- Arlington Historical Society
- National Park Service - A Historic Resources Study: The Civil War Defenses of Washington