Contra Costa County Demographics

A map of Contra Costa County's Population by Race

Race	2024 Pop	2020 Pop	2024 %	2020 %
White	443,990	455,421	38.1%	39.1%
Hispanic	321,749	314,900	27.6%	27.0%
Asian	217,115	214,520	18.6%	18.4%
Black	92,564	97,994	7.9%	8.4%
Multiracial	73,611	66,453	6.3%	5.7%
Native American/Other	15,983	16,639	1.4%	1.4%

Contra Costa County, California has an estimated population of 1,165,012, a less than 1% change from the 1,165,927 recorded in the 2020 Census. The population is 38.1% White, 27.6% Hispanic, 18.6% Asian, 7.9% Black, 6.3% Multiracial, and 1.4% Native American/Other. This demographic dot map shows the population of Contra Costa County, with one dot drawn for each person counted by the Census, color-coded by race.

Contra Costa is about as racially diverse as it was in the 2020 Census. It is more diverse than California overall. Demographers use a diversity index to measure the probability that two randomly selected individuals belong to different racial or ethnic groups. In Contra Costa County, that probability was 73.0% in 2020 and 73.3% in the most recent ACS estimates.

Contra Costa County is ranked the 9th most populous county in California, out of 58 counties. Contra Costa County was ranked the 9th most populous county in the 2020 Census.

Contra Costa County's White Population

443,990 residents of Contra Costa County, or 38.1% of the population, identify as White. The share of White residents in Contra Costa County is slightly higher than in California overall, where 33.8% of the population is White. Contra Costa County ranks 37th statewide in terms of White residents as a share of the population, out of 58 counties.

Since the 2020 Census, Contra Costa County's White population has declined by an estimated 2.5%. White residents' share of Contra Costa County's population has decreased from 39.1% to 38.1%.

Contra Costa County is more White than neighboring Alameda County (27.4% White), Solano County (33.2% White), San Mateo County (34.7% White), and San Joaquin County (26.8% White). Contra Costa County is less White than neighboring Napa County (48.6% White).

Contra Costa County's Black Population

92,564 residents of Contra Costa County, or 7.9% of the population, identify as Black. The share of Black residents in Contra Costa County is slightly higher than in California overall, where 5.2% of the population is Black. Contra Costa County ranks 4th statewide in terms of Black residents as a share of the population, out of 58 counties.

Since the 2020 Census, Contra Costa County's Black population has declined by an estimated 5.5%. Black residents' share of Contra Costa County's population has decreased from 8.4% to 7.9%.

Contra Costa County is more Black than neighboring San Mateo County (2% Black), San Joaquin County (6.6% Black), and Napa County (1.7% Black). Contra Costa County is less Black than neighboring Alameda County (9.3% Black), and Solano County (12.3% Black).

Contra Costa County's Asian Population

217,115 residents of Contra Costa County, or 18.6% of the population, identify as Asian. The share of Asian residents in Contra Costa County is slightly higher than in California overall, where 15.3% of the population is Asian. Contra Costa County ranks 6th statewide in terms of Asian residents as a share of the population, out of 58 counties.

Since the 2020 Census, Contra Costa County's Asian population has grown by an estimated 1.2%. Asian residents' share of Contra Costa County's population has remained roughly unchanged at 18.6%.

Contra Costa County is more Asian than neighboring Solano County (15.9% Asian), San Joaquin County (18.2% Asian), and Napa County (8.1% Asian). Contra Costa County is less Asian than neighboring Alameda County (32.7% Asian), and San Mateo County (31% Asian).

Contra Costa County's Hispanic Population

321,749 residents of Contra Costa County, or 27.6% of the population, identify as Hispanic. The share of Hispanic residents in Contra Costa County is considerably lower than in California overall, where 40.2% of the population is Hispanic. Contra Costa County ranks 29th statewide in terms of Hispanic residents as a share of the population, out of 58 counties.

Since the 2020 Census, Contra Costa County's Hispanic population has grown by an estimated 2.2%. Hispanic residents' share of Contra Costa County's population has increased from 27.0% to 27.6%.

Contra Costa County is more Hispanic than neighboring Alameda County (23.4% Hispanic), and San Mateo County (24.9% Hispanic). Contra Costa County is less Hispanic than neighboring Solano County (29.6% Hispanic), San Joaquin County (42.5% Hispanic), and Napa County (36.4% Hispanic).

Contra Costa County's Native American/Other Population

15,983 residents of Contra Costa County, or 1.4% of the population, identify as American Indian/Alaska Native/Native Hawaiian/Pacific Islander/Other. The share of Native American/Other residents in Contra Costa County is comparable to the share in California overall, where 1.2% of the population is Native American/Other. Contra Costa County ranks 35th statewide in terms of Native American/Other residents as a share of the population, out of 58 counties.

Since the 2020 Census, Contra Costa County's Native American/Other population has declined by an estimated 3.9%. Native American/Other residents' share of Contra Costa County's population has remained roughly unchanged at 1.4%.

Contra Costa County is more Native American/Other than neighboring San Joaquin County (1.3% Native American/Other), and Napa County (0.9% Native American/Other). Contra Costa County is less Native American/Other than neighboring Alameda County (1.6% Native American/Other), Solano County (2% Native American/Other), and San Mateo County (2.1% Native American/Other).

Contra Costa County's Multiracial Population

73,611 residents of Contra Costa County, or 6.3% of the population, identify as Multiracial. The share of Multiracial residents in Contra Costa County is comparable to the share in California overall, where 4.4% of the population is Multiracial. Contra Costa County ranks 18th statewide in terms of Multiracial residents as a share of the population, out of 58 counties.

Since the 2020 Census, Contra Costa County's Multiracial population has grown by an estimated 10.8%. Multiracial residents' share of Contra Costa County's population has increased from 5.7% to 6.3%.

Contra Costa County is more Multiracial than neighboring Alameda County (5.6% Multiracial), San Mateo County (5.2% Multiracial), San Joaquin County (4.6% Multiracial), and Napa County (4.4% Multiracial). Contra Costa County is less Multiracial than neighboring Solano County (6.9% Multiracial).

Sources: Most recent population estimates are from the 2020-2024 American Community Survey 5-Year Estimates. 2020 population counts and map data are from 2020 Census State Redistricting Data. Geographic data are from Census TIGER/Line Shapefiles.