St. Onge township
- County:
- Lawrence County
- County Seat:
- No
- Area (mi²):
- 35.774
- State:
- South Dakota
St. Onge township is located in Lawrence County, South Dakota. St. Onge township has a 2026 population of 365. St. Onge township is currently growing at a rate of 1.67% annually and its population has increased by 11.62% since the most recent census, which recorded a population of 327 in 2020.
The median age in St. Onge township is 53.3 years: 64.1 years for males, and 53.2 years for females. For every 100 females there are 72.6 males.