1,160,925 people (2024 Census estimate, +1.1% since 2020)
391 square miles of land · 2,969 people per square mile
“Highest” and “lowest” are just order, not grades: a high rank for poverty or hazard losses means more of it. Each figure's source is in its section below.
5 active community water systems list Fairfax County in the area they serve, reporting 1,212,901 people served in all (a system that crosses county lines counts its whole population).
| FAIRFAX COUNTY WATER AUTHORITY surface water · local government · VA6059501 | 1,121,613 served |
| FORT BELVOIR buys surface water · private · VA6059450 | 39,303 served |
| VIENNA, TOWN OF buys surface water · local government · VA6059800 | 27,134 served |
| HERNDON, TOWN OF buys surface water · local government · VA6059550 | 24,601 served |
| TAUXEMONT groundwater · private · VA6059750 | 250 served |
Source: U.S. EPA Safe Drinking Water Information System (SDWIS), active community systems, . Look up any system's violations and test results with EPA's search using its ID.
About 543 people were held in Fairfax County's jail, in Vera's latest figure (2025). In 2020 it was about 555.
Source: Vera Institute of Justice, Incarceration Trends (built from federal Bureau of Justice Statistics jail surveys). Counties without their own jail, or that share one, may show no figure.
1 school district has its office in Fairfax County. School taxes are usually the largest part of a property tax bill.
Spent $3.8 billion — $3.4 billion to run schools, about $18,975 per student, plus $279.4 million on buildings and equipment. Money in: $2.5 billion local (mostly property tax), $929.1 million state, $289.5 million federal. Long-term debt: $1.6 billion.
Source: U.S. Census Bureau, 2023 Annual Survey of School System Finances. Districts are listed by the county of their main office; some serve neighboring counties too.
Source: County Health Rankings & Roadmaps 2025 (University of Wisconsin Population Health Institute), which gathers federal data (CDC, Census, and others); measures cover different recent years. Blank lines aren't reported for small counties.
Overall risk: Relatively High compared with other U.S. counties. FEMA estimates natural hazards cost Fairfax County about $219.1 million a year on average in buildings, crops and lives. Ability to bounce back (community resilience): Relatively Moderate; social vulnerability: Very Low.
Source: FEMA National Risk Index (December 2025), expected annual loss. Ratings compare counties nationwide; they're estimates, not predictions.
752 bridges in Fairfax County: 401 in good condition, 345 fair, and 6 poor (0.8%). “Poor” means a main part — the deck, the beams, or the supports — is rated 4 or lower on the federal 0–9 scale. It doesn't mean unsafe to drive; unsafe bridges are closed.
| CHAINBRIDGE RD NBL over LEESBURG PIKE; ROUTE 7 · built 1965 | 27,000 vehicles a day |
| WB DIAAH over HUNTER MILL ROAD · built 1961 | 22,000 vehicles a day |
| EDSALL ROAD over INTERSTATE 395 · built 1967 | 21,942 vehicles a day |
| SLEEPY HOLLOW ROAD over HOLMES RUN · built 1960 | 12,231 vehicles a day |
| OLD COLCHESTER RD. over POHICK CREEK · built 1950 | 2,323 vehicles a day |
| BEACH MILL ROAD over TRIBUTARY OF CLARKS BR. · built 1983 | 1,425 vehicles a day |
Source: Federal Highway Administration, National Bridge Inventory (2025 submission). Includes state, county and city bridges.
Federal grants paid for $608.6 million of work in Fairfax County in fiscal 2025, about $529 per resident — to the county, cities, schools, hospitals, nonprofits and others.
Source: USAspending.gov, grants by place of performance, fiscal 2025 (Oct. 2024 to Sept. 2025). Search it by county to see each award.
From Grants.gov: posted grants listing county governments as eligible, soonest deadline first; research-only and overseas programs left out; list updated 2026-10-13, refreshed weekly. 62 are open in all. Cities, towns, school districts and nonprofits have their own lists there.
General election: Tuesday, November 3, 2026. Early voting: 2026-09-18 to 2026-10-31. Last day to register to vote: 2026-10-23. Mail ballot request deadline: 2026-10-23. Election Day: 2026-11-03.
Source: Virginia Department of Elections: upcoming elections · Virginia Department of Elections: voter FAQ · Virginia Department of Elections: absentee voting
The budget, property tax rates, audits, local officials and offices for Fairfax County come from the county's own records, which we haven't gathered — not gathered, never hidden. See what a full county site looks like, or ask to have Fairfax County built: brayden.ozark@gmail.com.
More of Virginia: the state government and every county in Virginia.
Nearby counties: Fairfax city (2 mi) · Falls Church city (6 mi) · Arlington County (10 mi) · Manassas Park city (10 mi) · Alexandria city (10 mi) · Manassas city (13 mi).