Union
- County:
- Edmunds County
- County Seat:
- No
- Area (mi²):
- 36.109
- State:
- South Dakota
Union is located in Edmunds County, South Dakota. Union has a 2025 population of 29 . Union is currently declining at a rate of 0% annually and its population has increased by 11.54% since the most recent census, which recorded a population of 26 in 2020.
The median age in Union is 50.3 years: 0 years for males, and 0 years for females. For every 100 females there are 21.1 males.