San Francisco Bay Area Counties

9 counties · 7.6 million people (2025) · 6,910 sq mi

The San Francisco Bay Area is made up of 9 counties, as defined by the Association of Bay Area Governments (ABAG). Together they had 7,619,201 people in 2025.

Map of the 9 counties of the San Francisco Bay Area region with county names and major cities
The 9 counties of the San Francisco Bay Area region (yellow) with the largest cities. Boundaries: U.S. Census Bureau, 2025. Free to use with attribution (CC BY 4.0).
PDF (Letter) 340 KBPNG (2400 px) 185 KB

The 9 counties of the San Francisco Bay Area region

Sorted by population.

CountyCounty seatPopulation 2025Change since 2020Land area (sq mi)
Santa Clara CountySan Jose1,914,391−1.1%1,291
Alameda CountyOakland1,636,630−2.7%738
Contra Costa CountyMartinez1,170,070+0.4%717
San Francisco CountySan Francisco826,079−6%47
San Mateo CountyRedwood City743,568−2.7%449
Sonoma CountySanta Rosa486,444−0.5%1,575
Solano CountyFairfield455,376+0.4%822
Marin CountySan Rafael253,694−3.3%520
Napa CountyNapa132,949−3.7%752

Printable map

The PDF is a vector file for Letter paper; the PNG is 2400 pixels wide. Both are free to use with a credit to WhichCounty.

County maps of California

Other metro areas

Sources