San Mateo County Demographics

A map of San Mateo County's Population by Race

San Mateo County, California had a population of 764,442 in 2020. It was 36.1% White, 1.9% Black, 29.8% Asian, 25.0% Hispanic, 2.1% Native American/Other, and 5.1% Multiracial. This map presents the population of San Mateo County, with one dot drawn for each person counted in the 2020 Census, color-coded by race.

San Mateo County is the 15th most populous county of the 58 counties in California.

San Mateo County's White Population

275,902 residents of San Mateo County identify as White, or 36.1%. This makes the White share of the population of San Mateo County roughly similar to the White share of the population of California (34.7% White). Of the 58 counties in California, San Mateo County is ranked #41 in terms of White residents as a share of the population.

San Mateo County is more White than neighboring Alameda County (28.1% White), and Santa Clara County (28.7% White). San Mateo County is less White than neighboring San Francisco County (39.1% White), Santa Cruz County (53.7% White), and Contra Costa County (39.1% White).

San Mateo County's Black Population

14,701 residents of San Mateo County identify as Black, or 1.9%. This makes the Black share of the population of San Mateo County roughly similar to the Black share of the population of California (5.4% Black). Of the 58 counties in California, San Mateo County is ranked #26 in terms of Black residents as a share of the population.

San Mateo County is more Black than neighboring Santa Cruz County (1.1% Black). San Mateo County is less Black than neighboring San Francisco County (5.2% Black), Alameda County (9.5% Black), Contra Costa County (8.4% Black), and Santa Clara County (2.2% Black).

San Mateo County's Asian Population

227,783 residents of San Mateo County identify as Asian, or 29.8%. This makes the Asian share of the population of San Mateo County larger than the Asian share of the population of California (15.1% Asian). Of the 58 counties in California, San Mateo County is ranked #4 in terms of Asian residents as a share of the population.

San Mateo County is more Asian than neighboring Santa Cruz County (4.5% Asian), and Contra Costa County (18.4% Asian). San Mateo County is less Asian than neighboring San Francisco County (33.7% Asian), Alameda County (32.1% Asian), and Santa Clara County (38.9% Asian).

San Mateo County's Hispanic Population

191,386 residents of San Mateo County identify as Hispanic, or 25.0%. This makes the Hispanic share of the population of San Mateo County less than the Hispanic share of the population of California (39.4% Hispanic). Of the 58 counties in California, San Mateo County is ranked #33 in terms of Hispanic residents as a share of the population.

San Mateo County is more Hispanic than neighboring San Francisco County (15.6% Hispanic), and Alameda County (23.4% Hispanic). San Mateo County is less Hispanic than neighboring Santa Cruz County (34.8% Hispanic), Contra Costa County (27% Hispanic), and Santa Clara County (25.2% Hispanic).

San Mateo County's Native American/Other Population

15,701 residents of San Mateo County identify as American Indian/Alaska Native/Native Hawaiian/Pacific Islander/Other, or 2.1%. This makes the Native American/Other share of the population of San Mateo County roughly similar to the Native American/Other share of the population of California (1.3% Native American/Other). Of the 58 counties in California, San Mateo County is ranked #22 in terms of Native American/Other residents as a share of the population.

San Mateo County is more Native American/Other than neighboring San Francisco County (1.3% Native American/Other), Alameda County (1.7% Native American/Other), Santa Cruz County (1% Native American/Other), Contra Costa County (1.4% Native American/Other), and Santa Clara County (1% Native American/Other).

San Mateo County's Multiracial Population

38,969 residents of San Mateo County identify as Multiracial, or 5.1%. This makes the Multiracial share of the population of San Mateo County roughly similar to the Multiracial share of the population of California (4.1% Multiracial). Of the 58 counties in California, San Mateo County is ranked #29 in terms of Multiracial residents as a share of the population.

San Mateo County is more Multiracial than neighboring Santa Cruz County (4.9% Multiracial), and Santa Clara County (4% Multiracial). San Mateo County is less Multiracial than neighboring San Francisco County (5.2% Multiracial), Alameda County (5.3% Multiracial), and Contra Costa County (5.7% Multiracial).

Source: 2020 Census State Redistricting Data and Census TIGER/Line Shapefiles.