COUNTY · VA
Fairfax County, Virginia
Fairfax County is a county in Virginia with FIPS code 51059 and an estimated population of 1,141,878 (Census 2023), 1st largest of 133 in the state.
County facts
- Name
- Fairfax County
- State
- Virginia
- Type
- county
- FIPS code
- 51059
- State FIPS
- 51
- Population (2023)
- 1,141,878
- Change since 2020
- -0.6%
- State rank
- 1 of 133
Population is the Census Bureau’s Vintage 2023 estimate.
Questions
What is the FIPS code for Fairfax County?
Fairfax County, Virginia has the five-digit FIPS code 51059: 51 for the state and 059 for the county.
What state is Fairfax County in?
Fairfax County is in Virginia.
How do I know if an address is in this county?
Use the address lookup. ZIP codes and city names can cross county lines, so an address is the reliable check.
Sources: U.S. Census Bureau geographic reference files; Census Bureau Population Estimates, Vintage 2023. Last reviewed 2026-10-27.