How many people live in Seneca County, OH?
Updated Apr. 6, 2026Refreshed annually
In 2024, there were about 54,700 people living in Seneca County, OH. That makes Seneca County the 47th-most populous county in Ohio. It is home to 0.46% of people living in the state.
54.7K
population of Seneca County, OH (2024)
0.46%
County share of the Ohio population (2024)
About 54,700 people lived in Seneca County, OH in 2024.
Population estimates, 2000–2024
What are Seneca County, OH’s age demographics?
About 11,100 Seneca County residents are aged 65 and older in 2024. That represents 20.3% of its population. For comparison, the age group represents 19.1% of Ohio’s population and 18% in the US overall.
Another 11,500 Seneca County residents, or 21.1% of the population, were children under 18. For comparison, the age group represents 21.7% of Ohio’s population and 21.6% in the US overall.
A lower share of Seneca County, OH's population is aged 25–44 than the US as a whole.
Population estimates by age group, (2024)
What are Seneca County, OH’s racial and ethnic demographics?
Non-Hispanic white residents make up 87.7% of the Seneca County, OH population, higher than the national share of 57.5%. Seneca County, OH also has a larger share of people identifying as non-Hispanic two or more races (2.5%) than the US overall (2.5%).
In contrast, Seneca County’s Hispanic population accounts for 6.2%, below the 20% nationwide, and the non-Hispanic Black or African American population makes up 2.4% of the county, compared with 12.6% nationally.
Racial and ethnic make up differ based on location. These figures reflect how people identified their race alone (not in combination with other races), and separate out Hispanic or Latino ethnicity, following Census reporting standards.
Seneca County, OH has a higher share of a non-Hispanic white population than Ohio as a whole.
Population estimates by race and ethnicity, (2024)
The largest city or town in Seneca County, OH is Tiffin with about 17,700 residents in 2024.
Cities and towns in Seneca County, OH ranked by population
Population (2024), includes only portions within county
| City or town | Population | |
|---|---|---|
| 1. | Tiffin | 17,729 |
| 2. | Fostoria (pt.) | 9,101 |
| 3. | Clinton | 4,037 |
| 4. | Hopewell | 2,731 |
| 5. | Loudon | 2,191 |
| 6. | Eden | 1,997 |
| 7. | Pleasant | 1,487 |
| 8. | Seneca | 1,436 |
| 9. | Jackson | 1,411 |
| 10. | Thompson | 1,382 |
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Methodology
USAFacts standardizes data, in areas such as time and demographics, to make it easier to understand and compare.
The analysis was generated with the help of AI and reviewed by USAFacts for accuracy.
Page sources
USAFacts endeavors to share the most up-to-date information available. We sourced the data on this page directly from government agencies; however, the intervals at which agencies publish updated data vary.
