Solano County, California
County seat: Fairfield · Population 455,376 (2025) · 822 sq mi
Solano County is the 19th most populous of California's 58 counties, with 455,376 people (2025 estimate). Its county seat is Fairfield. The map shows its 7 cities and towns and the 6 neighboring counties.
Solano County facts
- County seat
- Fairfield
- Population (2025 estimate)
- 455,376 +0.4% since 2020
- Land area
- 822 sq mi 46th largest of 58
- Water area
- 84 sq mi
- Population density
- 554 per sq mi
- Established
- 1850
- Named after
- Chief Solano Native American chief
- Largest city
- Vallejo 123,287
- Median household income
- $100,401
- Cities and towns
- 7 plus 4 CDPs
- ZIP codes
- 21
- Time zone
- Pacific
- FIPS code
- 06095
Cities and towns in Solano County
Solano County has 7 incorporated cities, towns and villages. Populations count the people living inside Solano County; cities that cross a county line also list the other counties.
| Name | Type | Population 2025 | Also in |
|---|---|---|---|
| Vallejo | City | 123,287 | |
| Fairfield (county seat) | City | 122,489 | |
| Vacaville | City | 103,850 | |
| Suisun City | City | 29,454 | |
| Benicia | City | 26,401 | |
| Dixon | City | 21,116 | |
| Rio Vista | City | 10,523 |
Unincorporated communities (CDPs)
Census-designated places are communities without their own city government; the county provides their services.
| Community | Population | Also in |
|---|---|---|
| Hartley | 2,431 | |
| Allendale | 1,734 | |
| Green Valley | 1,364 | |
| Elmira | 319 |
ZIP codes in Solano County
21 ZIP codes reach into Solano County. ZIP codes ignore county lines, so some also cover a neighboring county.
- 94503 also Napa County
- 94510
- 94512
- 94533
- 94534
- 94535
- 94571 also Sacramento County
- 94585
- 94589
- 94590
- 94591 also Napa County
- 94592
- 95612 also Yolo County
- 95616 also Yolo County
- 95618 also Yolo County
- 95620 also Yolo County
- 95625
- 95687
- 95688
- 95690 also Sacramento County
- 95694 also Yolo County
Population of Solano County, 2020–2025
Solano County grew by 1,820 people (+0.4%) between April 2020 and July 2025: 4,580 more births than deaths and a net loss of 2,712 people from migration.
| Year (July 1) | Population |
|---|---|
| 2020 | 452,895 |
| 2021 | 451,048 |
| 2022 | 449,852 |
| 2023 | 451,377 |
| 2024 | 455,076 |
| 2025 | 455,376 |
Neighboring counties
- Napa County northwest · 132,949 people
- Yolo County north · 224,410 people
- Contra Costa County south · 1,170,070 people
- Sacramento County east · 1,618,460 people
- Sonoma County west · 486,444 people
- Marin County west · 253,694 people
Printable Solano 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) (128 KB)
- PNG (2400 px) (98 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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