Eureka township
- County:
- McPherson County
- County Seat:
- No
- Area (mi²):
- 36.272
- State:
- South Dakota
Eureka township is located in McPherson County, South Dakota. Eureka township has a 2026 population of 186. Eureka township is currently growing at a rate of 0.54% annually and its population has increased by 5.68% since the most recent census, which recorded a population of 176 in 2020.
The median age in Eureka township is 58 years: 42.5 years for males, and 61.2 years for females. For every 100 females there are 173.3 males.