COUNTY · SD
Union County, South Dakota
Union County is a county in South Dakota with FIPS code 46127 and an estimated population of 17,183 (Census 2023), 13th largest of 66 in the state.
County facts
- Name
- Union County
- State
- South Dakota
- Type
- county
- FIPS code
- 46127
- State FIPS
- 46
- Population (2023)
- 17,183
- Change since 2020
- +1.9%
- State rank
- 13 of 66
Population is the Census Bureau’s Vintage 2023 estimate.
Questions
What is the FIPS code for Union County?
Union County, South Dakota has the five-digit FIPS code 46127: 46 for the state and 127 for the county.
What state is Union County in?
Union County is in South Dakota.
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.