County Maps US

Fairfax County, Virginia

The most populous of Virginia's 133 counties and independent cities.

CountyFIPS 51059

Within Virginia
Fairfax County, highlighted, with the areas around it. Boundaries generalised from the 2025 Census cartographic boundary file; neighbour fills carry no data.

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Population
1,167,873
+19,275 (+1.7%) since 2020
Land area
391
square miles. A further 3.8% of the total area is water
Population density
2,987
people per square mile, computed rather than published
County seat
Fairfax
Seat of county government.
Established
1742
283 years ago
Largest city
Herndon town
Population 25,506 for the whole place, which extends beyond this county.

Sources: US Census Bureau, Population Estimates Program, Vintage 2025 Population Estimates, released 26 March 2026; US Census Bureau, Gazetteer Files, 2025 Gazetteer Files, released 10 September 2025; Wikidata (CC0), Wikidata. Retrieved 30 August 2026.

Satellite view

Aerial imagery of Fairfax County with its boundary drawn on top. A map shows you the shape; this shows you what is inside it, and which side of the line a place falls on.

Aerial view of Fairfax County, Virginia from the USGS National Map, with its boundary outlined
Imagery: USGS National Map, USGS Imagery Only, public domain, requested from USGS by your browser when you reach this point on the page, at 713 by 800 pixels. The boundary is the 2025 Census cartographic boundary file, reprojected to Web Mercator to match the imagery. You can also open the USGS National Map viewer.

Where Fairfax County ranks

Position among the 133 counties and independent cities of Virginia, and among all 3,144 US counties and county-equivalents. Computed from the figures on this page.

MeasureValueIn VirginiaNationally
Population1,167,8731st of 13342nd of 3,144
Land area391 sq mi47th of 1332,571st of 3,144
Population density2,987 per sq mi12th of 13336th of 3,144
Median household income$153,6372nd of 1334th of 3,143

Full data for Fairfax County

Every figure below is attributed to the Census Bureau product it came from, with the vintage of that product.
MeasureValueSource and vintage
Population1,167,873Vintage 2025 Population Estimates
Population in 20201,148,598Vintage 2025 Population Estimates
2020 estimates base?1,150,294Vintage 2025 Population Estimates
Land area391 sq mi2025 Gazetteer Files
Water area15.5 sq mi2025 Gazetteer Files
Total area406.5 sq mi2025 Gazetteer Files
Population density?2,987 per sq miComputed: Vintage 2025 estimates divided by 2025 Gazetteer land area
Median household income$153,637American Community Survey 2020-2024 5-Year Estimates
Median home value$732,800American Community Survey 2020-2024 5-Year Estimates
Median age39.1American Community Survey 2020-2024 5-Year Estimates
Households414,101American Community Survey 2020-2024 5-Year Estimates
Housing units430,047American Community Survey 2020-2024 5-Year Estimates

Sources: US Census Bureau, Population Estimates Program, Vintage 2025 Population Estimates, released 26 March 2026; US Census Bureau, Gazetteer Files, 2025 Gazetteer Files, released 10 September 2025; US Census Bureau, American Community Survey, American Community Survey 2020-2024 5-Year Estimates, released 29 January 2026. Population density is computed here, not published: it divides the Vintage 2025 population estimate by the 2025 Gazetteer land area, which are two different Census products. Retrieved 30 August 2026.

How the population changed

The Census Bureau publishes the components behind an estimate, not just the total. For the year to July 2025:

Births minus deaths
+6,234
12,104 births, 5,870 deaths
Net migration
+1,796
More people moved in than moved out.

Source: US Census Bureau, Population Estimates Program, Vintage 2025 Population Estimates, released 26 March 2026. Retrieved 30 August 2026.

The 9 areas bordering Fairfax County

Ordered by the length of the border actually shared, which the Census Bureau publishes in its county adjacency file and which no other county reference presents.

Bordering areaStateShared borderPopulation
Prince William CountyVirginia37 mi502,966
Loudoun CountyVirginia18 mi449,749
Montgomery CountyMaryland18 mi1,074,582
Fairfax cityVirginia14 mi26,772
Charles CountyMaryland12 mi176,593
Alexandria cityVirginia11 mi160,662
Prince George's CountyMaryland8.0 mi970,374
Arlington CountyVirginia7.1 mi243,931
Falls Church cityVirginia6.0 mi15,159

Source: US Census Bureau, County Adjacency File, 2025 County Adjacency File, released 15 September 2025. Retrieved 30 August 2026.

Side by side

All 133 counties and independent cities of Virginia

Open the interactive Virginia county map, or jump straight to any of them.

Data on this page last rebuilt 30 August 2026. How these figures are produced.