St. Clair township
- County:
- Columbiana County
- County Seat:
- No
- Area (mi²):
- 29.458
- State:
- Ohio
St. Clair township is located in Columbiana County, Ohio. St. Clair township has a 2026 population of 7,591. St. Clair township is currently declining at a rate of -0.42% annually and its population has decreased by -2.34% since the most recent census, which recorded a population of 7,773 in 2020.
The median household income in St. Clair township is $57,672 with a poverty rate of 11.45%. The median age in St. Clair township is 51.3 years: 44.2 years for males, and 57.2 years for females. For every 100 females there are 101.8 males.