Washtenaw County, Michigan
County seat: Ann Arbor · Population 370,214 (2025) · 706 sq mi
Washtenaw County is the 6th most populous of Michigan's 83 counties, with 370,214 people (2025 estimate). Its county seat is Ann Arbor. It is part of the Southeast (Region 9) region, one of the 10 Michigan prosperity regions. The map shows its 8 cities and towns and the 6 neighboring counties.
Washtenaw County facts
- County seat
- Ann Arbor
- Population (2025 estimate)
- 370,214 −0.6% since 2020
- Land area
- 706 sq mi 27th largest of 83
- Water area
- 16 sq mi
- Population density
- 524 per sq mi
- Established
- 1822
- Largest city
- Ann Arbor 122,233
- Median household income
- $89,180
- Cities and towns
- 8 plus 1 CDPs
- ZIP codes
- 27
- Time zone
- Eastern
- FIPS code
- 26161
Cities and towns in Washtenaw County
Washtenaw County has 8 incorporated cities, towns and villages. Populations count the people living inside Washtenaw County; cities that cross a county line also list the other counties.
| Name | Type | Population 2025 | Also in |
|---|---|---|---|
| Ann Arbor (county seat) | City | 122,233 | |
| Ypsilanti | City | 19,766 | |
| Saline | City | 9,001 | |
| Chelsea | City | 5,424 | |
| Dexter | City | 4,461 | |
| Milan | City | 3,726 | Monroe County |
| Manchester | Village | 2,027 | |
| Barton Hills | Village | 323 |
Unincorporated communities (CDPs)
Census-designated places are communities without their own city government; the county provides their services.
| Community | Population | Also in |
|---|---|---|
| Whitmore Lake | 5,166 | Livingston County |
ZIP codes in Washtenaw County
27 ZIP codes reach into Washtenaw County. ZIP codes ignore county lines, so some also cover a neighboring county.
- 48103
- 48104
- 48105
- 48108
- 48109
- 48111 also Wayne and Monroe counties
- 48118
- 48130
- 48137 also Livingston County
- 48158 also Jackson County
- 48160 also Monroe County
- 48167 also Oakland and Wayne counties
- 48168 also Wayne County
- 48169 also Livingston County
- 48170 also Wayne County
- 48176 also Lenawee County
- 48178 also Oakland and Livingston counties
- 48189 also Livingston County
- 48190
- 48191 also Monroe County
- 48197
- 48198
- 49229 also Lenawee and Monroe counties
- 49236 also Lenawee County
- 49240 also Jackson County
- 49285 also Ingham, Jackson and Livingston counties
- 49287 also Lenawee County
Population of Washtenaw County, 2020–2025
Washtenaw County shrank by 2,051 people (−0.6%) between April 2020 and July 2025: 2,940 more births than deaths and a net loss of 4,381 people from migration.
| Year (July 1) | Population |
|---|---|
| 2020 | 371,814 |
| 2021 | 364,941 |
| 2022 | 367,307 |
| 2023 | 367,845 |
| 2024 | 368,956 |
| 2025 | 370,214 |
Neighboring counties
- Jackson County west · 159,552 people
- Wayne County east · 1,769,038 people
- Livingston County north · 197,315 people
- Lenawee County southwest · 97,779 people
- Monroe County southeast · 156,004 people
- Oakland County northeast · 1,288,337 people
Printable Washtenaw 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) (147 KB)
- PNG (2400 px) (74 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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