
Tiffin
- County:
- Seneca County
- County Seat:
- Yes
- Area (mi²):
- 7.234
- State:
- Ohio
Tiffin is a city located in Seneca County, Ohio. Tiffin has a 2025 population of 17,360. It is also the county seat of Seneca County. Tiffin is currently declining at a rate of -0.69% annually and its population has decreased by -3.38% since the most recent census, which recorded a population of 17,967 in 2020.
The average household income in Tiffin is $71,248 with a poverty rate of 12.3%. The median age in Tiffin is 36.7 years: 34.6 years for males, and 38.7 years for females.