Grenville township
- County:
- Day County
- County Seat:
- No
- Area (mi²):
- 33.553
- State:
- South Dakota
Grenville township is located in Day County, South Dakota. Grenville township has a 2026 population of 81. Grenville township is currently declining at a rate of 0% annually and its population has increased by 1.25% since the most recent census, which recorded a population of 80 in 2020.
The median household income in Grenville township is $115,938 with a poverty rate of 3.76%. The median age in Grenville township is 60.7 years: 65.9 years for males, and 40.3 years for females. For every 100 females there are 135.4 males.