About the Census

Every 10 years, the federal government is required to count all residents in the United States, citizens and noncitizens alike, through a national census.  The latest national census began in April 2020. The information is used to make sure everyone is equally represented in our political system and that government resources are allocated fairly. It is also used to make important decisions about community programs and services, like where to build homes and parks, establish public transit routes, build new roads and offer language access services.

The American Community Survey, or ACS, is different than the Decennial Census. The American Community Survey shows how we live—our education, housing, jobs, and more. The American Community Survey provides information about the social and economic needs of your community every year. The ACS:

  • Asks about topics not on the 2020 Census, such as education, employment, internet access, and transportation
  • Provides current information to communities every year.  It also provides local and national leaders with the information they need for programs, economic development, emergency management, and understanding local issues and conditions.
American Community Survey, 2021, 1-Year Estimates -
Language Spoken at Home by Ability to Speak English for the Population 5 Year + Older
Label Estimate Percentage Speaks English
less than "Very Well"
Total Individuals 5+ 699,990      
Speak only English 397,346 56.76%    
Spanish: 109,981 15.71% 42,518 6.07%
Chinese (incl. Mandarin, Cantonese): 68,883 9.84% 30,639 4.38%
Tagalog (incl. Filipino): 39,905 5.7% 15,483 2.21%
Ilocano, Samoan, Hawaiian,
or other Austronesian languages:
8,321 1.19% 2,641 0.38%
Arabic: 6,974 1.0% 3,242 0.46%
Russian: 6,669 0.95% 2,518 0.36%
Hindi: 6,147 0.88% 650 0.09%
Japanese: 5,463 0.78% 2,443 0.35%
Other languages of Asia: 4,439 0.63% 2,585 0.37%
Korean: 4,163 0.59% 1,587 0.23%


San Mateo County 2020 Census Race and Ethnicity