Northumberland County, Virginia
Quick answer: Northumberland County is a county in Virginia with its seat at Heathsville. Its estimated population in 2025 was 12,557, up 6.1% since 2020. It covers about 191 square miles of land.
| Type | county |
|---|---|
| County seat | Heathsville |
| Established | 1648 |
| Population, 2025 estimate | 12,557 |
| Population, 2020 estimate | 11,838 |
| Change 2020–2025 | 6.1% |
| Rank by population in Virginia | 107 of 133 |
Overview
Northumberland County is a county in the Commonwealth of Virginia, one of 95 in the state.[1] The county seat is Heathsville.[2] The county was established in 1648.[2] The name comes from Northumberland.[2]
Population of Northumberland County
The U.S. Census Bureau estimated the population of Northumberland County at 12,557 in July 2025, up 6.1% from the April 2020 base of 11,835.[1] That made it 107th of Virginia's 133 counties and independent cities by population. It ranked 30th for growth since 2020.[1]
From 2020 to 2025 the Census Bureau counted about 449 births and 1,116 deaths, so deaths outnumbered births by 667.[1] More people moved in from other parts of the United States than moved away. Net domestic migration was 1,402. Moves from abroad were -13.[1]
Geography
Northumberland County covers 191.4 square miles of land and 94.2 square miles of water.[3] By land area it ranks 88th of 133 in Virginia.[3] It had about 66 people per square mile in 2025, so it is mostly rural. Its geographic center lies near 37.86° N, 76.38° W.[3]
The county borders Accomack County, Lancaster County, Richmond County and Westmoreland County in Virginia, as well as land in Maryland.[4]
The U.S. Geological Survey place-name database lists 66 named streams, 19 lakes and reservoirs and 2 islands in the county.[5]
Towns
Northumberland County has one incorporated town: Kilmarnock (76, part), with its estimated 2025 population in brackets.[6] In Virginia, towns remain part of the county around them, unlike independent cities. "Part" means only the share of the town inside this county.
Frequently asked questions
What is the county seat of Northumberland County?
Heathsville.
What is the population of Northumberland County?
About 12,557 people in 2025, according to the U.S. Census Bureau.
How big is Northumberland County?
About 191 square miles of land, plus 94.2 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, Northumberland 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.co.northumberland.va.us
Boundary on the map: Census TIGERweb. See all counties and cities on the map.