Bay County, Michigan
County seat: Bay City · Population 102,123 (2025) · 442 sq mi
Bay County is the 20th most populous of Michigan's 83 counties, with 102,123 people (2025 estimate). Its county seat is Bay City. It is part of the East Central (Region 5) region, one of the 10 Michigan prosperity regions. The map shows its 5 cities and towns and the 6 neighboring counties.
Bay County facts
- County seat
- Bay City
- Population (2025 estimate)
- 102,123 −1.7% since 2020
- Land area
- 442 sq mi 79th largest of 83
- Water area
- 188 sq mi
- Population density
- 231 per sq mi
- Established
- 1857
- Named after
- Saginaw Bay bay within Lake Huron in eastern Michigan
- Largest city
- Bay City 31,868
- Median household income
- $61,763
- Cities and towns
- 5
- ZIP codes
- 17
- Time zone
- Eastern
- FIPS code
- 26017
Cities and towns in Bay County
Bay County has 5 incorporated cities, towns and villages. Populations count the people living inside Bay County; cities that cross a county line also list the other counties.
| Name | Type | Population 2025 | Also in |
|---|---|---|---|
| Bay City (county seat) | City | 31,868 | |
| Essexville | City | 3,284 | |
| Auburn | City | 2,039 | |
| Pinconning | City | 1,176 | |
| Midland | City | 176 | Midland County |
ZIP codes in Bay County
17 ZIP codes reach into Bay County. ZIP codes ignore county lines, so some also cover a neighboring county.
- 48604 also Saginaw County
- 48611
- 48613 also Gladwin County
- 48623 also Saginaw and Midland counties
- 48631
- 48634
- 48642 also Midland County
- 48650 also Arenac County
- 48652 also Gladwin and Midland counties
- 48658 also Arenac County
- 48659 also Arenac County
- 48706
- 48708 also Saginaw County
- 48710
- 48732
- 48747 also Saginaw County
- 48757 also Tuscola and Saginaw counties
Population of Bay County, 2020–2025
Bay County shrank by 1,740 people (−1.7%) between April 2020 and July 2025: 2,786 more deaths than births and a net gain of 1,022 people from migration.
| Year (July 1) | Population |
|---|---|
| 2020 | 103,739 |
| 2021 | 103,115 |
| 2022 | 102,736 |
| 2023 | 102,693 |
| 2024 | 102,432 |
| 2025 | 102,123 |
Neighboring counties
- Arenac County northeast · 15,068 people
- Saginaw County south · 187,688 people
- Tuscola County southeast · 52,680 people
- Midland County west · 83,754 people
- Gladwin County northwest · 26,077 people
- Huron County east · 30,530 people
Printable Bay 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) (131 KB)
- PNG (2400 px) (92 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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