
Union township
- County:
- Day County
- County Seat:
- No
- Area (mi²):
- 35.59
- State:
- South Dakota
Union township is located in Day County, South Dakota. Union township has a 2025 population of 66. Union township is currently declining at a rate of -2.94% annually and its population has decreased by -5.71% since the most recent census, which recorded a population of 70 in 2020.
The average household income in Union township is $107,041 with a poverty rate of 0%. The median age in Union township is 64.4 years: 64.2 years for males, and 69 years for females.