Fairfax County, officially the County of Fairfax, is a county in the Virginia, United States. With a population of 1,150,309 as of the 2020 census, it is the most populous county in Virginia, the most populous jurisdiction in the Washington metropolitan area, and the most populous location in the Washington–Baltimore combined statistical area. The county seat is Fairfax; however, because it is an independent city under Virginia law, the city of Fairfax is not part of the county.
The county is part of the Northern Virginia region and forms part of the suburban ring of Washington, D.C., the nation's capital. The county is predominantly suburban with some urban and rural pockets. It borders Montgomery County, Maryland to its north, Falls Church, Alexandria, Arlington County, and Prince George's County, Maryland to its east, Charles County, Maryland to its southeast, Prince William County to its southwest, and Loudoun County to its northwest.
The county is home to the offices of the director of national intelligence in McLean and the headquarters of four U.S. intelligence agencies: the Central Intelligence Agency at the George Bush Center for Intelligence in Langley, the National Geospatial-Intelligence Agency at Fort Belvoir, the National Reconnaissance Office in Chantilly, and the National Counterterrorism Center in McLean.
In academia, the county is home to the flagship campus of George Mason University in Fairfax, CIA University in Chantilly, Sherman Kent School for Intelligence Analysis in Reston, and several Northern Virginia Community College campuses. In the private sector, as of 2025, eleven of the Fortune 500 companies are headquartered in the county as of 2023.
In 2020, Fairfax County's median household income of $127,866 was the fifth-highest in the United States.
History
Prior to European settlement, present-day Fairfax County was initially inhabited by the Algonquian-speaking Doeg tribe.
17th century
In 1608, Captain John Smith documented the Doeg tribe's villages, which included Namassingakent and Nemaroughquand on the south bank of the Potomac River in present-day Fairfax County. By 1670, Virginian colonists from the Northern Neck region drove the Doeg Tribe out of present-day Fairfax County and into Maryland.
18th century
Fairfax County was formed in 1742 from the northern part of Prince William County, and was named after Thomas Fairfax, 6th Lord Fairfax of Cameron, proprietor of the Northern Neck.
The county's initial settlements were along the Potomac River. George Washington settled in Fairfax County and built his home, Mount Vernon, facing the Potomac. Gunston Hall, the home of George Mason, is nearby. Fort Belvoir is partly on the estate of Belvoir Manor, built along the Potomac by William Fairfax in 1741.
Thomas Fairfax, the only member of the British nobility ever to reside in the colonies, lived at Belvoir before moving to the Shenandoah Valley. The Belvoir mansion and several of its outbuildings were destroyed by fire immediately after the Revolutionary War in 1783, and George Washington noted the plantation complex deteriorated into ruins.
In 1757, the northwestern two-thirds of Fairfax County became Loudoun County. In 1789, part of Fairfax County was ceded to the federal government to form Alexandria County, then part of the District of Columbia.
19th century
Alexandria County was returned to Virginia in 1846, reduced in size by the secession of the independent city of Alexandria in 1870, and renamed Arlington County in 1920.
During the American Civil War the Battle of Chantilly, also known as Ox Hill, part of the Second Battle of Bull Run, was fought within Fairfax County. Other areas of Civil War conflict in the county included Minor's Hill, Munson's Hill, and Upton's Hill.
20th century
The Fairfax County town of Falls Church became an independent city in 1948. The Fairfax County town of Fairfax was named an independent city in 1961.
The federal government's growth during and after World War II spurred rapid growth in the county and transformed it from a rural to suburban region. Large businesses began settling in the county, and the opening of Tysons Corner Center spurred the rise of Tysons, Virginia. The technology boom and a steady government-driven economy created rapid growth and an increasingly large and diverse population. The economy has also made Fairfax County one of the nation's wealthiest counties.
A general aviation airport along U.S. Route 50 west of Seven Corners, Falls Church Airpark, operated in the county from 1948 to 1960. The facility's 2,650-foot unpaved runway was used extensively by private pilots and civil defense officials. Residential development, multiple accidents, and the demand for retail space led to its closure in 1960.
Geography and climate
According to the U.S. Census Bureau, the county has an area of 406 square miles (1,050 km2), of which 391 square miles (1,010 km2) is land and 15 square miles (39 km2) (3.8%) is water. There are about 44,400,000 trees that create a canopy covering 55.4% of the total land area.
Fairfax County is bounded on the north and southeast by the Potomac River. Across the river to the northeast is Washington, D.C., across the river to the north is Montgomery County, Maryland, and across the river to the southeast are Prince George's County, Maryland and Charles County, Maryland. The county is partially bounded on the north and east by Arlington County and the independent cities of Alexandria and Falls Church. It is bounded on the west by Loudoun County, and on the south by Prince William County.
Most of the county lies in the Piedmont region, with rolling hills and deep stream valleys, such as Difficult Run and its tributaries. West of Route 28, the hills give way to a flat, gentle valley that stretches west to the Bull Run Mountains in Loudoun County. Elevations in the county range from near sea level along the tidal sections of the Potomac River in the southeast portion of the county to more than 500 feet (150 m) in the Tysons area.
In 2023, the plant hardiness zone shifted from 7a to 7b. The Fairfax County News Letter predicts that Fairfax will shift to zone 8 in the next few decades as temperatures rise.
Adjacent jurisdictions
Geology
The Piedmont hills in the central county are made up of ancient metamorphic rocks such as schist, the roots of several ancestral ranges of the Appalachian Mountains. The western valley is floored with more recent shale and sandstone. This geology is similar to adjacent bands of rocks in Maryland and further south in Virginia along the eastern front of the Appalachian.
An area of 11 square miles (30 km2) of the county is known to be underlain with natural asbestos. Much of the asbestos is known to emanate from fibrous tremolite or actinolite. The threat was discovered in 1987, prompting the county to establish laws to monitor air quality at construction sites, control soil taken from affected areas, and require freshly developed sites to lay 6 inches (150 mm) of clean, stable material over the ground.
During the construction of Centreville High School, for instance, a large amount of asbestos-laden soil was removed and then trucked to Vienna for the construction of the I-66/Nutley Street interchange. Fill dirt then had to be trucked in to make the site level. Marine clays can be found in widespread areas of the county east of Interstate 95, mostly in the Franconia and Mount Vernon districts. These clays contribute to soil instability, leading to significant construction challenges for builders.
Demographics
Racial and ethnic composition
2020 census
As of the 2020 census, the county had a population of 1,150,309. The median age was 38.3 years. 23.3% of residents were under the age of 18 and 13.8% of residents were 65 years of age or older. For every 100 females there were 97.1 males, and for every 100 females age 18 and over there were 94.6 males age 18 and over.
The racial makeup of the county was 49.5% White, 9.6% Black or African American, 0.6% American Indian and Alaska Native, 20.4% Asian, 0.1% Native Hawaiian and Pacific Islander, 8.6% from some other race, and 11.3% from two or more races. Hispanic or Latino residents of any race comprised 17.3% of the population.
98.5% of residents lived in urban areas, while 1.5% lived in rural areas.
There were 411,055 households in the county, of which 35.3% had children under the age of 18 living with them and 23.3% had a female householder with no spouse or partner present. About 22.6% of all households were made up of individuals and 7.8% had someone living alone who was 65 years of age or older.
There were 427,149 housing units, of which 3.8% were vacant. Among occupied housing units, 65.7% were owner-occupied and 34.3% were renter-occupied. The homeowner vacancy rate was 0.7% and the rental vacancy rate was 5.4%.
The median income for a household in the county was $145,164, and the median income for a family was $174,085. 7.5% of the population were military veterans, and 65.5% had a bachelors degree or higher. In the county 5.6% of the population was below the poverty line, including 5.6% of those under age 18 and 5.7% of those age 65 or over, with 7.2% of the population without health insurance.
Socioeconomic characteristics
The median income for a household in the county was $145,164, and the median income for a family was $174,085. 7.5% of the population were military veterans, and 65.5% had a bachelors degree or higher. In the county 5.6% of the population was below the poverty line, including 5.6% of those under age 18 and 5.7% of those age 65 or over, with 7.2% of the population without health insurance.
Education
Primary education
The county is served by the Fairfax County Public Schools system, to which the county government allocates 52.2% of its budget. Including state and federal government contributions, along with citizen and corporate contributions, this brings the 2023 budget for the school system to $3.5 billion. The school system has estimated that, based on the 2023 fiscal year budget, the county would spend $18,772 on each student.
The Fairfax County Public School system contains the Thomas Jefferson High School for Science and Technology, a Virginia Governor's School. TJHSST consistently ranks at or near the top of all U.S. high schools due to the extraordinary number of National Merit semifinalists and finalists, its students' high average SAT scores, and the number of students who annually perform nationally recognized research in the sciences and engineering. A Governor's School, TJHSST draws students from five counties Fairfax County and other Northern Virginia counties, cities, and towns.
Catholic elementary and middle schools in the county fall under the Roman Catholic Diocese of Arlington and include Paul VI Catholic High School, Fairfax County's diocese-run Catholic high school, and Oakcrest School, an all-girls Catholic school in Fairfax County, which is not run by the diocese.
Colleges and universities
George Mason University is just outside the city of Fairfax, near the geographic center of Fairfax County. Northern Virginia Community College (NVCC) serves Fairfax County with campuses in Annandale and Springfield and a center in Reston that is a satellite branch of the Loudoun campus. The NVCC Alexandria campus borders Fairfax County. The Central Intelligence Agency University and its Sherman Kent School for Intelligence Analysis are both located in Fairfax County, specifically in Chantilly and Reston respectively. George Mason University faculty have twice won the Nobel Prize in Economics. George Mason University economics professors James M. Buchanan and Vernon L. Smith won it in 1986 and 2002, respectively.
The University of Fairfax, a for-profit proprietary college and alleged diploma mill was once headquartered in Vienna, Virginia. Virginia Commonwealth University's School of Medicine recently constructed a medical campus wing at Inova Fairfax Hospital in order to allow third- and fourth-year medical students to study at other state-of-the-art facilities in Northern Virginia.
Economy
Fairfax County's economy revolves around professional services and technology. Many residents work for the government or contractors of the federal government. The government is the largest employer, with Fort Belvoir in southern Fairfax the county's single largest source of federal employment. Fairfax County has a gross county product of approximately $95 billion.
Major employers in the county include Airbus, Volkswagen Group of America, Hilton Worldwide, DXC Technology, Northrop Grumman, Science Applications International Corporation (SAIC), Leidos, Booz Allen Hamilton, Gannett, Capital One, General Dynamics, ICF International, Freddie Mac, Sallie Mae, ManTech International, Mars, NII, and NVR. The county is home to eleven Fortune 500 company headquarters, 11 Hispanic 500 companies, and five companies on the Black Enterprise 500 list.
The county's economy is supported by the Fairfax County Economic Development Authority, which provides services and information to promote Fairfax County as a leading business and technology center. The FCEDA is the nation's largest non-state economic development authority. Fairfax County is also home to the Northern Virginia Technology Council, a trade association for local technology companies. Fairfax County has a higher concentration of high-tech workers than Silicon Valley.
Tysons
Tysons, located in the county, is Virginia's largest office market and the nation's largest suburban business district, with 26,600,000 square feet (2,470,000 m2) of office space. It is the country's 12th-largest business district and is expected to grow substantially in the coming decades. It contains a quarter of the county's total office space inventory, which was 105,200,000 square feet (9,770,000 m2) as of 2006, representing roughly the same size as the Lower Manhattan region of New York City.
In October 2011, Forbes described the area as "the place where the Internet was invented, but today it looks increasingly like the center of the global military-industrial complex", because it is home to the nation's first ISPs, many of which are now defunct, and attracts numerous defense contractors that have relocated from other states to or near Tysons Corner.
Tysons draws over 100,000 workers from around the Washington metropolitan area, and draws 55,000 shoppers daily to its two super-regional malls, Tysons Corner Center and Tysons Galleria, compared to 62,500 shoppers daily in Washington, D.C..
After years of delays attributed to stalling and controversy, the $5.2 billion expansion of the Washington Metro Silver Line in Virginia from Washington, D.C., to Dulles International Airport was funded by the Federal Transit Administration in December 2008. The Silver Line added four stations in Tysons, including a station between Tysons Corner Center and Tysons Galleria.
Along with the expansion of Washington Metro, Fairfax County government has a plan to "urbanize" the Tysons area. The plan calls for a private-public partnership and a grid-like street system to make Tysons a more urban environment, tripling available housing to allow more workers to live near their workplaces. The goal is to have 95% of Tysons Corner within 1⁄2-mile (800 m) of a metro station.