The population of the nine-county San Francisco Bay Area was approximately 7.66 million in 2025
of Bay Area residents lived in the three most populous cities (San Jose, San Francisco and Oakland) in 2025
Between 2020 and 2022, the total population in the Bay Area decreased by 162k, the first decrease in decades
Introduction
How many people live in the Bay Area?
In 2025, almost 7.7 million people lived in the nine-county, 7,000-square-mile Bay Area region. Residents are spread throughout the 101 cities and in various unincorporated communities, the size and density of which vary widely.
Regional Performance
Over the long term, regional population growth has been strong. However, as of the early 2020s that trend is showing signs of reversing.
Regional population dynamics are driven by multiple forces, including the prevalence of job opportunities and overall affordability, including the availability of housing opportunities at all income levels. Since 1970, the Bay Area’s population has grown by over 60%, adding about 3 million new residents.
In the 2010s, the Bay Area kept growing, thanks to a strong economy. But by the end of that decade, growth started to slow. After 2020 when the COVID-19 pandemic hit the population actually began to shrink. From 2020 to 2025, the region has lost about 109,000 people, or around 1.4% of its population. In fact, the early 2020s were the first years the Bay Area’s population dropped in more than 50 years.
The population of the nine-county San Francisco Bay Area increased by 65% between 1970 and 2025
As of 2025, regional population was down 1.4% from its peak of 7.77 million in early 2020
Regional Distribution
The distribution of Bay Area residents between center cities and suburban communities has been relatively stable for the past two decades.
Vital Signs groups jurisdictions in the Bay Area based on their proximity to the Bay, with the three largest cities—San Jose, San Francisco and Oakland—classified as the “Big Three.” Cities along the Bay are referred to as “Bayside” cities, while cities beyond this core are categorized as “Inland, Coastal and Delta.” The remainder of the Bay Area is designated as “Unincorporated.”
Since 1970, the share of residents living in Inland, Coastal and Delta cities has increased from 12% to 25%. The distribution of residents in the Bay Area has remained relatively stable since 2005, with approximately 29% residing in the Big Three cities; 36% in Bayside cities; 25% in Inland, Coastal and Delta cities; and 10% in Unincorporated areas. However, since the COVID-19 pandemic, the Big Three's share of the population has declined by about half a percentage point.
In 2025, the largest Bay Area county by population was Santa Clara County at approximately 1.9 million residents
In 2025, the smallest Bay Area county by population was Napa County at approximately 136,000 residents
Local Focus
Census tracts and Priority Development Areas (PDAs) are small geographic units that are useful for analyzing population density and growth over time.
A census tract is a small area that the U.S. Census Bureau uses to study where people live and how communities change over time. In the Bay Area, the densest tracts are typically found in San Francisco and Oakland. However, the Inland, Delta and Coastal regions have experienced the most significant population growth since 1970.
PDAs are places near public transit that are planned for new homes, jobs and community amenities. Examining neighborhoods now identified as PDAs reveals historical population trends and allows us to track where growth is occurring.
of census tracts in Solano County had a population growth of more than 100% from 1990 to 2024
The population of the North San Jose PDA in Santa Clara County increased by 66% (almost 14,000 residents) between 2014 and 2024
Sources & Methodology
All historical data reported for Census geographies (county, city and tract) use current legal boundaries and names.
Population estimates for Bay Area counties and cities are from the California Department of Finance, which are as of January 1st of each year.
Population estimates for Bay Area tracts are from the decennial Census (1990-2020, April 1 of each year) and the American Community Survey (2013-2024 five-year rolling averages). Estimates of population density for tracts use land acres as the denominator.
A Priority Development Area (PDA) is a locally-designated area with frequent transit service, where a jurisdiction has decided to concentrate most of its housing and jobs growth for development in the foreseeable future. The Plan Bay Area 2050+ boundaries are used here.
Population estimates for PDAs are allocated from tract-level Census population counts using an area ratio. For example, if a quarter of a Census tract lies with in a PDA, a quarter of its population will be allocated to that PDA. Estimates of population density for PDAs use gross acres as the denominator; however, since PDAs are water-clipped, this means that gross acres and land acres are equivalent.
The following is a list of cities and towns by geographic area:
Big Three: San Jose, San Francisco and Oakland
Bayside: Alameda, Albany, Atherton, Belmont, Belvedere, Berkeley, Brisbane, Burlingame, Campbell, Colma, Corte Madera, Cupertino, Daly City, East Palo Alto, El Cerrito, Emeryville, Fairfax, Foster City, Fremont, Hayward, Hercules, Hillsborough, Larkspur, Los Altos, Los Altos Hills, Los Gatos, Menlo Park, Mill Valley, Millbrae, Milpitas, Monte Sereno, Mountain View, Newark, Pacifica, Palo Alto, Piedmont, Pinole, Portola Valley, Redwood City, Richmond, Ross, San Anselmo, San Bruno, San Carlos, San Leandro, San Mateo, San Pablo, San Rafael, Santa Clara, Saratoga, Sausalito, South San Francisco, Sunnyvale, Tiburon, Union City, Vallejo and Woodside
Inland, Delta and Coastal: American Canyon, Antioch, Benicia, Brentwood, Calistoga, Clayton, Cloverdale, Concord, Cotati, Danville, Dixon, Dublin, Fairfield, Gilroy, Half Moon Bay, Healdsburg, Lafayette, Livermore, Martinez, Moraga, Morgan Hill, Napa, Novato, Oakley, Orinda, Petaluma, Pittsburg, Pleasant Hill, Pleasanton, Rio Vista, Rohnert Park, San Ramon, Santa Rosa, Sebastopol, Sonoma, St. Helena, Suisun City, Vacaville, Walnut Creek, Windsor and Yountville
Unincorporated: All unincorporated towns
California Department of Finance: Population and Housing Estimates
Table E-4: Population Estimates for Counties and State (1970-2025)
Bay Area Jurisdiction Centroids (2020)
Computed using 2020 US Census TIGER/Line Shapefile boundaries
IPUMS NHGIS, University of Minnesota
1990-2020
U.S. Census Bureau: American Community Survey
2013-2024
Table B01003
Priority Development Areas (Plan Bay Area 2050+)