Jefferson township
- County:
- Union County
- County Seat:
- No
- Area (mi²):
- 47.679
- State:
- South Dakota
Jefferson township is located in Union County, South Dakota. Jefferson township has a 2026 population of 50. Jefferson township is currently declining at a rate of -1.96% annually and its population has decreased by -1.96% since the most recent census, which recorded a population of 51 in 2020.
The median age in Jefferson township is 31.9 years: 32.5 years for males, and 31.7 years for females. For every 100 females there are 95.1 males.