Key Findings

The Bay Area’s population grew faster in the 2010s than in the 2000s, with three of the four North Bay counties growing at the slowest rate over the decade.

Between 2010 and 2020, the Bay Area’s population grew by 9 percent, adding 615,000 residents. This growth rate was an increase over the prior decade, during which the region’s population grew by 5 percent. Alameda, San Francisco, San Mateo, and Solano Counties grew more than twice as fast in the 2010s than in the 2000s. Marin and Santa Clara Counties both experienced an increase of several percentage points in population growth between the 2000s and the 2010s. Meanwhile, Contra Costa County’s population growth saw little change between the 2000 and 2010s, and it's remained consistently above 10 percent since the turn of the century.

By contrast, population growth rates in Napa and Sonoma Counties plummeted, with both counties only seeing a 1 percent increase in residents between 2010 and 2020. Three of the four North Bay counties (Marin, Napa, and Sonoma) grew more slowly than the other parts of the region, even as population growth accelerated in Marin County during the 2010s. As the map below shows, many census tracts in these North Bay counties saw a net decrease in residents during the 2010s. This trend was especially prevalent in unincorporated areas outside of population hubs such as Santa Rosa, San Rafael, and Vallejo. The outlier in the North Bay was Solano County, whose population grew nearly 10 percent in the 2010s, especially in and around Fairfield and Vacaville. Notably, Solano County forms a corridor between the Bay Area and the Sacramento metropolitan area, which was one of California’s fastest-growing parts in the last decade.

As the census tract- and city-level maps above show, population growth in the 2010s was particularly concentrated in neighborhoods lining the San Francisco Bay: Mission Bay and Dogpatch in San Francisco, Redwood City and San Mateo, the northside of San Jose and the city of Milpitas, Fremont and Hayward, West Oakland and Emeryville, and West Berkeley and Albany. Other areas of rapid growth include the northeast part of Contra Costa County (Pittsburg, Oakley, and Brentwood), Dublin in Alameda County, the aforementioned Solano County (particularly the city of Rio Vista), and the southern tip of Santa Clara County (Morgan Hill and Gilroy). Meanwhile, as the city-level map reveals, unincorporated areas in Sonoma, Napa, and Santa Clara Counties saw a net decline in residents during the 2010s, while all but three cities and towns (Windsor, Ross, and St. Helena) grew in population size.

Asian American and multiracial populations grew the most, while Native American, Black, and white communities declined in size.

In 2000, people of color and multiracial people made up half (50 percent) of the Bay Area’s population; in 2020, that figure rose to 64 percent. The Bay Area has added more than 872,000 Asian American residents and 576,000 Latinx residents over the last two decades. The region’s 2.15 million Asian Americans — comprising a multitude of ethnic and cultural communities — now constitute the largest population of color in the Bay Area. While comprising a small share of the population, there has also been rapid growth in the number of multiracial (from 3.5 percent in 2010 to 5.1 percent in 2020) and “other” (0.3 percent in 2010 to 0.6 percent in 2020) residents.

During the same period, the Bay Area’s population decreased by a quarter million white residents, 25,000 Black residents, and 2,400 Native American residents. As the graph below shows, the rate of population decline slowed for white and Native American residents in the 2010s compared to the 2000s, but the decline continued nonetheless. The large decrease in white residents is the result of multiple factors: migration out of the region and state, a population that skews older than most communities of color, and a greater share of white residents in mixed-race families whose children are more likely to identify as multiracial. California has also experienced an exodus of Black residents over the past few decades, in no small part due to housing scarcity and rising costs of living.

The Bay Area’s Asian American population growth slightly accelerated from the 2000s to the 2010s (from 29 percent growth to 31 percent). Conversely, Pacific Islander and Latinx population growth in the region notably slowed in the 2010s compared to the prior decade. The US as a whole experienced a net decline in its Mexican immigrant population in the 2010s, as more residents moved from the US to Mexico than vice versa. Due to US-based childbirths and migration from other parts of Latin America, Latinx population growth in the Bay Area in the 2010s still exceeded the growth rate for all residents combined (13 percent, compared to 9 percent for all residents). Nonetheless, shifting political, economic, and demographic conditions — improvements to the Mexican economy, declining Mexican birth rates, and increasingly restrictive US immigration policies and practices — have had a notable effect on the Bay Area’s Latinx communities in recent years.

The landscape of racial and ethnic diversity in the Bay Area also varies from county to county, in no small part due to the different housing development and economic patterns that characterize different parts of the region.

• The two East Bay counties (Alameda and Contra Costa) are home to some of the region’s prominent historical Black communities and have a higher share of Black residents than the region as a whole (9 percent and 8 percent respectively, compared to 6 percent regionwide). Compared to the region overall, Alameda County has a larger Asian American population (32 percent, compared to 28 percent regionwide) and a smaller white population (28 percent, compared to 36 percent regionwide). Those trends are reversed in Contra Costa County, with its population being 18 percent Asian American and 39 percent white.
• Three of the four North Bay counties (Marin, Napa, and Sonoma) have some of the smallest Asian American and Black populations in the region. These three counties are the only Bay Area counties where at least half of the residents were white in 2020. They also were the slowest-growing counties in the 2010s. Marin County, the whitest county in the Bay Area (66 percent), has relatively few Latinx residents (19 percent, compared to 24 percent regionwide), whereas Latinx people make up more than one-third of residents (35 percent) in the agriculture-rich Napa County. Solano County resembles nearby Contra Costa County more closely than the rest of the North Bay. Just one-third (34 percent) of its residents are white, and the county has the largest share of Black residents (13 percent) in the entire Bay Area.
• All three counties on the Peninsula or in the South Bay (San Francisco, San Mateo, and Santa Clara) have relatively small Black communities and large Asian American populations. Nearly two in five (39 percent) Santa Clara County residents were Asian American in 2020. San Francisco has the smallest share of Latinx residents in the Bay Area (16 percent), while San Mateo County is the only part of the region where the Pacific Islander population rate exceeds 1 percent.
• The proportion of residents who identified as Native American (0.2 percent regionwide), multiracial (5.1 percent), and “other” (0.6 percent) was relatively consistent across counties. No county had a share of Native American residents exceeding 0.6 percent or “other” residents larger than 0.8 percent. The share of multiracial residents by county ranged from 4 percent (Santa Clara) to 6.8 percent (Solano) in 2020.

The Bay Area’s youth population declined between 2010 and 2020.

While the Bay Area’s population increased by more than 600,000 during the 2010s, the number of residents under the age of 18 fell by more than 33,000. This 2 percent decline in the regional youth population marked the acceleration of a trend from the prior decade, in which the Bay Area’s youth population dropped by less than 1 percent. Put otherwise, the Bay Area’s population growth since 2000 has been driven entirely by a net increase in the number of adults. These regional trends mirror patterns at the state and national level: between 2010 and 2020, there was a net decline in the under-18 population in California and the US. However, the Bay Area consistently had a smaller share of youth: in 2020, 20 percent of Bay Area residents were under the age of 18, compared to 22 percent of Californians and all US residents.

Changes in the youth population also varied at the subregional level, as the graph below shows. In four of nine counties, the youth population has increased since 2010. San Francisco’s youth population grew most quickly at 5 percent, while the North Bay’s youth population fell by 10 percent in Sonoma County and by 12 percent in Napa County. Alameda and San Francisco Counties saw their youth population shrink in the 2000s and grow in the 2010s, while the youth population in Napa and Santa Clara County expanded in the 2000s before it declined in the 2010s.

Across every major racial and ethnic group, the share of young people decreased between 2000 and 2020. For Black, Pacific Islander, and multiracial residents, these declines were particularly pronounced: young people made up 26 percent of Black Bay Area residents in 2000, compared to just 18 percent in 2020. For Pacific Islanders, the share of youth dropped from 29 percent to 20 percent. Multiracial residents experienced a drop in the youth rate from 45 to 36 percent. While the actual number of youth identifying as Asian American, multiracial, and “other” all increased between 2010 and 2020, youth population rates decreased for all these groups because the increase in adults outpaced the increase in children.

Despite these common trends in population change, youth population rates varied across racial and ethnic communities: 20 percent of the entire Bay Area population was under the age of 18 in 2020, compared to 28 percent Latinx residents and 14 percent white residents. Youth comprise a larger share of communities of color, compared to the white population. About 36 percent of multiracial Bay Area residents in 2020 were younger than 18 years old, indicative of a growing number of mixed-race families in recent generations.

Nevertheless, the overall trends show a shrinking youth population, which will create challenges for the region in the years ahead. While the share of older adults reaching retirement age will grow, it may become harder to fulfill the care needs of older adults with a smaller young, local workforce coming of age and entering the job market. Moreover, rising costs of living and ongoing housing scarcity will continue to make it harder for younger adults to move into the Bay Area, especially those who work in essential occupations like education and social services. For the sake of the region’s future generations, it is crucial that we continue to fight for a Bay Area that allows children and their loved ones to thrive.

Recommendations

Since 2010, the Bay Area’s population has grown in size, become more diverse, and grown older. Policymakers, local governments, and community leaders alike must be prepared to meet the shifting needs of local residents, particularly in the many different communities of color driving population growth across the Bay Area. At the same time, decision-makers must also address the region-wide challenges in equitable housing and infrastructure that have existed long before 2010. To ensure a more equitable and inclusive Bay Area in the 2020s and beyond, we must:

1. Prioritize the construction of affordable housing in all Bay Area counties, including the upzoning of neighborhoods restricted to single-family homes. The Bay Area has continued to grow amidst a decades-long crisis in housing affordability and availability. Even if demographic projections anticipate slower population growth in the following decades, it’s still imperative for officials across the region to prioritize the development of affordable housing. The unhoused population has surged in recent years, and thousands of renters across the region face the risk of homelessness with the elimination of pandemic-era eviction moratoriums. Accelerated development may require deliberate approaches to enabling higher-density construction in suburban and exurban neighborhoods, especially as local resistance has impeded California’s recent law enabling duplex construction in residential areas zoned for single units.

2. Accelerate the development of transportation and social services infrastructure in lower-density areas of the region, such as the North Bay. If current growth trends continue unabated, there will be an increasingly large population asymmetry between areas like the East Bay and South Bay, and the low-density, majority-white areas of the North Bay. The growing population in the North Bay will require more than just housing construction, as less densely populated areas will need different infrastructure and services to meet the needs of a larger, more diverse population. Transportation and social services infrastructure are essential elements for all Bay Area residents. As such, plans for housing development in low-density communities must prioritize these infrastructural concerns as well. 

3. Expand multilingual support across public institutions, especially in Asian and Latin American languages beyond the common threshold languages. Latinx and Asian American residents in particular have driven population growth in the Bay Area during the 21st century. Many local Asian American residents speak languages beyond those regularly covered in translated government materials, such as Mandarin, Cantonese, Tagalog, and Vietnamese. There are also smaller communities of indigenous Latin Americans who speak languages other than Spanish. Local public systems must understand the diversity within Asian American and Latinx communities to ensure that harder-to-reach populations receive the information and support they might need.

4. Invest in social supports and care infrastructure for older adults and young people alike. As mentioned earlier, the shrinking share of young people in the Bay Area signals potential challenges on the horizon: the region will have to figure out how to sustain a workforce that can support local communities, and in particular fulfill the complex care needs of a growing older adult population. Local governments must deepen their investments in healthcare, housing, and other social programs for older adults, especially as fewer children means that more elders won’t have family to serve as caregivers. At the same time, the shrinking youth population mustn’t become a justification to disinvest in foundational supports for young people. Becoming a region where all families can afford to raise children in safe, healthy, and opportunity-rich communities is imperative to the Bay Area’s future.

*Ian Castro contributed data analysis to this research during his internship with PolicyLink in 2022. 

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