Originally the property of a blue-blooded English colonist, the land Fort Belvoir is built on belonged to the Culpepper family and was handed down to Lord Thomas Fairfax, 6th Lord Fairfax. In 1734, Lord Fairfax convinced his cousin, Col. William Fairfax, to move to Virginia and take charge of the family property. Col. Fairfax built a large estate on the family land, and named it "Belvoir" ("Beautiful to see"). The Fairfax family departed Virginia on business shortly before the American Revolution, and the land fell to public domain. In the1780s the Fairfax manor burned to the ground, and its ruins are still on base grounds.


In 1912 Congress transferred the 8,656 acres of land back to the War Department. Three years later, the area was converted into a rifle range and training camp for the U.S Army's Engineer School. With the U.S entering World War I in 1917, construction of a more permanent training camp began. The camp was renamed Camp A. A. Humphreys after Major General Andrew A. Humphreys.


Several schools became established at Camp A. A Humphreys during WWI: The Engineer Replacement & Training Camp, Engineers Officer Training, the Army Gas School (one of the first chemical weapons defense training programs in the US), and the School of Military Mining. At the end of the war in 1918, Camp A.A. Humphreys was used as a center for troops to demobilize before returning to regular civilian life. In 1922 Camp A.A. Humphreys was renamed Fort Humphreys, and later became Fort Belvoir in 1935.


Since the 1930s Fort Belvoir has primarily been a technical and engineering training center and unit home, and host of various military units and government agencies; until the 1980s it was home of the US Army Engineering School, and continues to be home of the principal engineering development and testing laboratory.