St. Clair County, Michigan
County seat: Port Huron · Population 160,486 (2025) · 722 sq mi
St. Clair County is the 13th most populous of Michigan's 83 counties, with 160,486 people (2025 estimate). Its county seat is Port Huron. It is part of the East (Region 6) region, one of the 10 Michigan prosperity regions. The map shows its 10 cities and towns and the 3 neighboring counties.
St. Clair County facts
- County seat
- Port Huron
- Population (2025 estimate)
- 160,486 +0.1% since 2020
- Land area
- 722 sq mi 24th largest of 83
- Water area
- 115 sq mi
- Population density
- 222 per sq mi
- Established
- 1820
- Same name
- One of 4 St. Clair Counties in the US
- Named after
- Lake Saint Clair, St. Clair River
- Largest city
- Port Huron 28,273
- Median household income
- $71,270
- Cities and towns
- 10 plus 3 CDPs
- ZIP codes
- 23
- Time zone
- Eastern
- FIPS code
- 26147
Cities and towns in St. Clair County
St. Clair County has 10 incorporated cities, towns and villages. Populations count the people living inside St. Clair County; cities that cross a county line also list the other counties.
| Name | Type | Population 2025 | Also in |
|---|---|---|---|
| Port Huron (county seat) | City | 28,273 | |
| Marysville | City | 9,868 | |
| St. Clair | City | 5,833 | |
| Algonac | City | 4,109 | |
| Marine City | City | 3,997 | |
| Capac | Village | 1,943 | |
| Yale | City | 1,873 | |
| Memphis | City | 309 | Macomb County |
| Emmett | Village | 236 | |
| Richmond | City | 1 | Macomb County |
Unincorporated communities (CDPs)
Census-designated places are communities without their own city government; the county provides their services.
| Community | Population | Also in |
|---|---|---|
| Pearl Beach | 4,506 | |
| Lakeport | 742 | |
| Ruby | 714 |
ZIP codes in St. Clair County
23 ZIP codes reach into St. Clair County. ZIP codes ignore county lines, so some also cover a neighboring county.
- 48001
- 48002
- 48006
- 48014 also Lapeer County
- 48022
- 48023
- 48027
- 48028
- 48032 also Sanilac County
- 48039
- 48040
- 48041 also Macomb County
- 48049
- 48054
- 48059
- 48060
- 48063
- 48064
- 48074
- 48079
- 48097 also Sanilac County
- 48416 also Sanilac and Lapeer counties
- 48444 also Lapeer County
Population of St. Clair County, 2020–2025
St. Clair County grew by 101 people (+0.1%) between April 2020 and July 2025: 3,052 more deaths than births and a net gain of 3,120 people from migration.
| Year (July 1) | Population |
|---|---|
| 2020 | 160,386 |
| 2021 | 160,268 |
| 2022 | 159,886 |
| 2023 | 160,279 |
| 2024 | 160,304 |
| 2025 | 160,486 |
Neighboring counties
- Macomb County southwest · 886,221 people
- Sanilac County north · 40,083 people
- Lapeer County west · 89,516 people
Printable St. Clair 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) (153 KB)
- PNG (2400 px) (116 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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