COUNTY · AR
Union County, Arkansas
Union County is a county in Arkansas with FIPS code 05139 and an estimated population of 37,397 (Census 2023), 21st largest of 75 in the state.
County facts
- Name
- Union County
- State
- Arkansas
- Type
- county
- FIPS code
- 05139
- State FIPS
- 05
- Population (2023)
- 37,397
- Change since 2020
- -3.9%
- State rank
- 21 of 75
Population is the Census Bureau’s Vintage 2023 estimate.
Questions
What is the FIPS code for Union County?
Union County, Arkansas has the five-digit FIPS code 05139: 05 for the state and 139 for the county.
What state is Union County in?
Union County is in Arkansas.
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.