Ontonagon County, Michigan
County seat: Ontonagon · Population 5,823 (2025) · 1,311 sq mi
Ontonagon County is the 82nd most populous of Michigan's 83 counties, with 5,823 people (2025 estimate). Its county seat is Ontonagon. It is part of the Upper Peninsula (Region 1) region, one of the 10 Michigan prosperity regions. The map shows its 1 city or town and the 6 neighboring counties.
Ontonagon County facts
- County seat
- Ontonagon
- Population (2025 estimate)
- 5,823 +0.3% since 2020
- Land area
- 1,311 sq mi 3rd largest of 83
- Water area
- 2,430 sq mi
- Population density
- 4 per sq mi
- Established
- 1843
- Named after
- Ontonagon River river in Michigan
- Largest city
- Ontonagon 2,277
- Median household income
- $54,398
- Cities and towns
- 1 plus 8 CDPs
- ZIP codes
- 12
- Time zone
- Eastern
- FIPS code
- 26131
Cities and towns in Ontonagon County
Ontonagon County has 1 incorporated place. Populations count the people living inside Ontonagon County; cities that cross a county line also list the other counties.
| Name | Type | Population 2025 | Also in |
|---|---|---|---|
| Ontonagon (county seat) | Village | 1,264 |
Unincorporated communities (CDPs)
Census-designated places are communities without their own city government; the county provides their services.
| Community | Population | Also in |
|---|---|---|
| White Pine | 369 | |
| Mass City | 299 | |
| Ewen | 281 | |
| Bruce Crossing | 257 | |
| Rockland | 246 | |
| Bergland | 138 | |
| Greenland | 76 | |
| Lake Gogebic | 72 |
ZIP codes in Ontonagon County
12 ZIP codes reach into Ontonagon County. ZIP codes ignore county lines, so some also cover a neighboring county.
- 49910
- 49912
- 49925
- 49929
- 49947 also Gogebic County
- 49948 also Houghton County
- 49952 also Houghton County
- 49953
- 49960
- 49965 also Houghton County
- 49967 also Houghton and Iron counties
- 49971
Population of Ontonagon County, 2020–2025
Ontonagon County grew by 16 people (+0.3%) between April 2020 and July 2025: 406 more deaths than births and a net gain of 428 people from migration.
| Year (July 1) | Population |
|---|---|
| 2020 | 5,799 |
| 2021 | 5,868 |
| 2022 | 5,889 |
| 2023 | 5,880 |
| 2024 | 5,866 |
| 2025 | 5,823 |
Neighboring counties
- Gogebic County southwest · 14,285 people
- Houghton County east · 37,842 people
- Keweenaw County northeast · 2,186 people
- Cook County, Minnesota northwest · 5,522 people
- Ashland County, Wisconsin west · 16,203 people
- Iron County southeast · 11,757 people
Printable Ontonagon 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) (145 KB)
- PNG (2400 px) (84 KB)
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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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