Prince William County, Virginia
Quick answer: Prince William County is a county in Virginia with its seat at Manassas. Its estimated population in 2025 was 502,966, up 4.3% since 2020. It covers about 335 square miles of land.
| Type | county |
|---|---|
| County seat | Manassas |
| Established | 1731 |
| Population, 2025 estimate | 502,966 |
| Population, 2020 estimate | 482,838 |
| Change 2020–2025 | 4.2% |
| Rank by population in Virginia | 2 of 133 |
Overview
Prince William County is one of the 95 counties of Virginia.[1] The county seat is Manassas.[2] The county was established in 1731.[2] The name comes from Prince William, Duke of Cumberland.[2]
Population of Prince William County
The U.S. Census Bureau estimated the population of Prince William County at 502,966 in July 2025, up 4.3% from the April 2020 base of 482,205.[1] That made it 2nd of Virginia's 133 counties and independent cities by population. It ranked 38th for growth since 2020.[1]
From 2020 to 2025 the Census Bureau counted about 32,385 births and 13,345 deaths, a natural increase of 19,040.[1] More people moved away to other parts of the United States than moved in. Net domestic migration was -19,504. Moves from abroad added 20,657.[1]
Geography
Prince William County covers 335.3 square miles of land and 11.9 square miles of water.[3] By land area it ranks 58th of 133 in Virginia.[3] It had about 1,500 people per square mile in 2025, so it is one of the more densely settled places in the state. Its geographic center lies near 38.70° N, 77.48° W.[3]
The county borders Fairfax County, Fauquier County, Loudoun County, the City of Manassas Park, the City of Manassas and Stafford County in Virginia, as well as land in Maryland.[4]
The U.S. Geological Survey place-name database lists 53 named streams, 8 named summits, 20 lakes and reservoirs and 2 islands in the county.[5]
Towns
Prince William County has 4 incorporated towns. With their estimated 2025 populations, they are: Dumfries (6,405), Haymarket (1,602), Occoquan (1,078), Quantico (597).[6] In Virginia, towns remain part of the county around them, unlike independent cities.
Frequently asked questions
What is the county seat of Prince William County?
Manassas.
What is the population of Prince William County?
About 502,966 people in 2025, according to the U.S. Census Bureau.
How big is Prince William County?
About 335 square miles of land, plus 11.9 square miles of water.
References
- [1] U.S. Census Bureau, County Population Totals and Components of Change: 2020-2025 (Vintage 2025) – last checked 11/08/2026
- [2] Wikidata, Prince William County, Virginia (open data, CC0) – last checked 11/08/2026
- [3] U.S. Census Bureau, 2024 Gazetteer Files: Counties – last checked 11/08/2026
- [4] U.S. Census Bureau, County Adjacency File (2024) – last checked 11/08/2026
- [5] U.S. Geological Survey, Geographic Names Information System (GNIS), Domestic Names – last checked 11/08/2026
- [6] U.S. Census Bureau, City and Town Population Totals: 2020-2025 – last checked 11/08/2026
Official website: www.pwcgov.org
Boundary on the map: Census TIGERweb. See all counties and cities on the map.