Fort Belvoir Fort Belvoir is a United States Army installation and a census - designated place ( CDP ) in Fairfax County , Virginia , United States . Originally , it was the site of the Belvoir plantation . Today , Fort Belvoir is home to a number of important United States military organizations . The population of Fort Belvoir was 7 , 100 at the 2010 census . History . The base was founded during World War I as Camp A . A . Humphreys , named for Andrew A . Humphreys . The post was renamed Fort Belvoir in the 1930s in recognition of the Belvoir plantation that once occupied the site , but the adjacent United States Army Corps of Engineers Humphreys Engineer Center retains part of the original namesake . Fort Belvoir was initially the home of the Army Engineer School prior to its relocation in the 1980s to Fort Leonard Wood , in Missouri . It was also the home of the United States Army Engineer Research and Development Laboratory . As a result of the 2005 Base Realignment and Closure Commission , Fort Belvoir had a substantial increase in the number of people stationed or employed there . All major Washington , DC - area National Geospatial - Intelligence Agency ( NGA ) facilities , including those in Bethesda , MD ; Reston , VA ; and Washington , DC were consolidated at a new facility , the NGA Campus East , situated on the former Engineer Proving Ground site . The cost of the new center was $ 2 . 4 billion . Units and agencies . Fort Belvoir serves as the headquarters for the Defense Logistics Agency , the Defense Acquisition University , the Defense Contract Audit Agency , the Defense Technical Information Center , the United States Army Intelligence and Security Command , the Missile Defense Agency , the Defense Threat Reduction Agency , and the National Geospatial - Intelligence Agency , all agencies of the United States Department of Defense . Fort Belvoir is home to the Virginia National Guard ' s 29th Infantry Division ( Light ) and elements of ten Army Major Commands ; nineteen different agencies and direct reporting units of the Department of Army ; eight elements of the United States Army Reserve and the Army National Guard ; and twenty - six Department of Defense agencies . Also located here are the 249th Engineer Battalion ( Prime Power ) , the Military District of Washington ' s 12th Aviation Battalion which provides rotary - wing movement to the DoD and Congress , a Marine Corps detachment , a United States Air Force activity , United States Army Audit Agency , and an agency from the Department of the Treasury . In addition , Fort Belvoir is home to National Reconnaissance Office ' s ( NRO ) Aerospace Data Facility , East ( ADF - E ) . The site . The Fort Belvoir site was originally the home of William Fairfax , the cousin and land agent of Thomas Fairfax , 6th Lord Fairfax of Cameron the proprietor of the Northern Neck , which once stood on land now on the base . William Fairfax purchased the property in 1738 when his cousin arranged for him to be appointed customs agent ( tax collector ) for the Potomac River , and William erected an elegant brick mansion overlooking the river , moving in with his family in 1740 . Lord Fairfax came to America in 1747 and stayed less than year at the Belvoir estate before moving to Greenway Court . The Fairfax family lived at Belvoir for over 30 years , but eldest son ( and heir ) George William Fairfax sailed to England on business in 1773 , never to return . The manor home was destroyed by fire in 1783 . The ruins of the Belvoir Mansion and the nearby Fairfax family grave site are listed on the National Register of Historic Places . William Fairfax served in the Royal Navy as a young man and all of his sons ( except his eldest , George William ) served in uniform , two of whom were killed in combat . Demographics . Fort Belvoir is also a census - designated place . Nearby CDPs are Mount Vernon , Virginia ( northeast ) and Franconia , Virginia ( northwest ) . As of the census of 2000 , there were 7 , 176 people , 1 , 904 households , and 1 , 867 families residing in the CDP . The population density was 314 . 1 / km² ( 813 . 7 / sq mi ) . There were 2 , 056 housing units at an average density of 90 . 0 / km² ( 233 . 1 / sq mi ) . The racial makeup of the CDP was 55 . 7 % White , 31 . 8 % African American , 1 . 7 % Asian , 0 . 5 % Native American , 0 . 9 % Pacific Islander , 5 . 1 % from other races , and 4 . 3 % from two or more races . Hispanic or Latino of any race were 10 . 5 % of the population . There were 1 , 904 households out of which 84 . 3 % had children under the age of 18 living with them , 84 . 3 % were married couples living together , 11 . 5 % had a female householder with no husband present , and 1 . 9 % were non - families . 1 . 7 % of all households were made up of individuals and none had someone living alone who was 65 years of age or older . The average household size was 3 . 66 and the average family size was 3 . 68 . In the CDP the population was spread out with 44 . 4 % under the age of 18 , 10 . 1 % from 18 to 24 , 41 . 3 % from 25 to 44 , 3 . 9 % from 45 to 64 , and 0 . 3 % who were 65 years of age or older . The median age was 22 years . For every 100 females there were 101 . 1 males . For every 100 females age 18 and over , there were 96 . 9 males . The median income for a household in the CDP was $ 39 , 592 , and the median income for a family was $ 39 , 107 . Males had a median income of $ 30 , 625 versus $ 25 , 817 for females . The per capita income for the CDP was $ 12 , 453 . About 4 . 7 % of families and 5 . 6 % of the population were below the poverty line , including 6 . 5 % of those under age 18 and none of those age 65 or over .