Seneca County, Ohio
County seat: Tiffin · Population 54,522 (2025) · 551 sq mi
Seneca County is the 47th most populous of Ohio's 88 counties, with 54,522 people (2025 estimate). Its county seat is Tiffin. The map shows its 8 cities and towns and the 6 neighboring counties.
Seneca County facts
- County seat
- Tiffin
- Population (2025 estimate)
- 54,522 −1% since 2020
- Land area
- 551 sq mi 16th largest of 88
- Water area
- 2 sq mi
- Population density
- 99 per sq mi
- Established
- 1820
- Named after
- Seneca indigenous people of North America
- Largest city
- Tiffin 17,803
- Median household income
- $66,025
- Cities and towns
- 8 plus 7 CDPs
- ZIP codes
- 20
- Time zone
- Eastern
- FIPS code
- 39147
Cities and towns in Seneca County
Seneca County has 8 incorporated cities, towns and villages. Populations count the people living inside Seneca County; cities that cross a county line also list the other counties.
| Name | Type | Population 2025 | Also in |
|---|---|---|---|
| Tiffin (county seat) | City | 17,803 | |
| Fostoria | City | 8,976 | Hancock and Wood counties |
| Attica | Village | 863 | |
| Bloomville | Village | 845 | |
| Green Springs | Village | 637 | Sandusky County |
| Bettsville | Village | 584 | |
| Republic | Village | 538 | |
| New Riegel | Village | 279 |
Unincorporated communities (CDPs)
Census-designated places are communities without their own city government; the county provides their services.
| Community | Population | Also in |
|---|---|---|
| Flat Rock | 340 | |
| Bascom | 298 | |
| Kansas | 200 | |
| Fort Seneca | 113 | |
| Melmore | 112 | |
| McCutchenville | 89 | Wyandot County |
| Old Fort | 81 |
ZIP codes in Seneca County
20 ZIP codes reach into Seneca County. ZIP codes ignore county lines, so some also cover a neighboring county.
- 43316 also Wyandot and Hancock counties
- 43410 also Sandusky County
- 43457 also Wood and Sandusky counties
- 44802 also Hancock County
- 44807 also Huron County
- 44809
- 44811 also Huron, Sandusky and Erie counties
- 44815
- 44818 also Crawford County
- 44828
- 44830 also Hancock and Wood counties
- 44836 also Sandusky County
- 44841 also Sandusky County
- 44844 also Wyandot County
- 44853
- 44854 also Crawford County
- 44861
- 44867
- 44882 also Wyandot and Crawford counties
- 44883
Population of Seneca County, 2020–2025
Seneca County shrank by 558 people (−1%) between April 2020 and July 2025: 572 more deaths than births and a net loss of 5 people from migration.
| Year (July 1) | Population |
|---|---|
| 2020 | 55,061 |
| 2021 | 54,975 |
| 2022 | 54,650 |
| 2023 | 54,719 |
| 2024 | 54,694 |
| 2025 | 54,522 |
Neighboring counties
- Sandusky County north · 58,655 people
- Huron County east · 58,250 people
- Wyandot County southwest · 21,567 people
- Crawford County southeast · 41,896 people
- Hancock County west · 75,034 people
- Wood County northwest · 134,176 people
Printable Seneca County map
The PDF is a vector file with real text: it prints sharp on Letter paper and you can search it for a town. The PNG is 2400 pixels wide for slides and documents. Both are free to use with a credit to WhichCounty.
- PDF (Letter) (86 KB)
- PNG (2400 px) (55 KB)
Paste this code to embed the map on your site:
Sources
- Boundaries: U.S. Census Bureau, 2025 Cartographic Boundary Files (1:500,000).
- Population: Census Bureau county and city estimates, Vintage 2025. CDP populations: American Community Survey 2020–2024.
- Places and ZIP codes: Census Bureau 2026 Gazetteer and 2020 ZIP Code Tabulation Area relationship files.
- County seat, founding year and name origin: Wikidata (CC0), checked against state sources.
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