Contra Costa County, California

2024 results by precinct

674 precincts · 528,904 votes cast

Harris · D+38

Harris +50

Trump +50

Real precinct boundaries. Hover for vote totals.

38 presidential elections

Year	Won	Margin	Democratic	Republican	Total
2024	D	+37.9%	356,008	155,308	528,904
2020	D	+45.3%	416,386	152,877	581,316
2016	D	+43.0%	319,287	115,956	473,014
2012	D	+35.1%	290,824	136,517	439,145
2008	D	+37.6%	306,983	136,436	453,244
2004	D	+25.8%	257,254	150,608	413,028
2000	D	+21.7%	224,338	141,373	381,478
1996	D	+20.6%	196,512	123,954	352,602
1992	D	+21.4%	194,960	112,965	382,823
1988	D	+3.2%	169,411	158,652	331,511
1984	R	−9.9%	140,994	172,331	316,318
1980	R	−12.8%	107,398	144,112	287,545
1976	R	−1.1%	123,742	126,598	256,534
1972	R	−10.6%	111,718	139,044	256,884
1968	D	+1.9%	101,668	97,486	218,917
1964	D	+27.0%	113,071	65,011	178,245
1960	D	+6.0%	93,622	82,922	177,123
1956	R	−2.2%	71,733	74,971	147,051
1952	D	+1.2%	69,060	67,453	137,281
1948	D	+14.6%	50,277	36,958	91,376
1944	D	+28.1%	47,831	26,816	74,785
1940	D	+24.5%	30,900	18,627	50,040
1936	D	+45.6%	26,007	9,604	35,975
1932	D	+21.6%	17,218	10,907	29,214
1928	R	−22.0%	8,573	13,495	22,349
1924	R	−48.0%	1,114	9,061	16,573
1920	R	−39.2%	3,483	9,041	14,182
1916	D	+2.8%	6,092	5,731	13,011
1912	D	+39.4%	3,290	0	8,350
1908	R	−31.6%	1,599	3,336	5,504
1904	R	−34.8%	1,257	2,833	4,529
1900	R	−16.2%	1,549	2,165	3,797
1896	R	−13.9%	1,381	1,834	3,269
1892	R	−9.5%	1,332	1,631	3,149
1888	R	−12.4%	1,177	1,518	2,758
1884	R	−14.3%	1,114	1,496	2,678
1880	R	−12.6%	1,010	1,302	2,312
1876	R	−17.2%	837	1,184	2,021

Demographics

Race, ethnicity, and ancestry

Click any group to see the ancestries typically reported within it.

American

100.0%

African American

6.6%

Multiple ancestry combinations reported; no single grouping above 1%.

American Indian, Alaska Native, Native Hawaiian, and Pacific Islander combined.

Source · American Community Survey 5-year estimates, 2024 release. Ancestry is a self-reported, multiple-response item; ancestry percentages do not sum to the parent race percentage.

Age distribution by sex

Median age: 40.5 in this county, 39.1 nationally

Male

Age

Female

0.7%

85+

1.3%

2.3%

75–84

2.9%

4.6%

65–74

5.3%

6.4%

55–64

6.6%

6.7%

45–54

6.8%

7.0%

35–44

7.1%

6.1%

25–34

6.1%

4.1%

18–24

3.9%

8.5%

5–17

8.2%

2.7%

2.6%

Source · American Community Survey 5-year estimates, 2024 release.

Median household income

2024 inflation-adjusted dollars

$127,229

Contra Costa County ranks in the top 0.5% of US counties.

Contra Costa County$127,229

California$99,122

United States$80,734

Source · American Community Survey 5-year estimates, 2024 release.

Poverty rate

All persons below federal poverty line

8.4%

Children face moderate poverty.

Children under 1818.0%

Working age (18–64)100.0%

Seniors (65+)18.0%

Source · American Community Survey 5-year estimates, 2024 release.

Language at home

Population aged 5 and older

0.0%

speak English only

Source · ACS 5-year estimates, 2024.

Religious adherents

Adherents per capita by tradition

Catholic & Orthodox

27.0%

Other Christian

5.9%

Non-Christian

2.8%

Baptist

2.3%

Pentecostal & Holiness

1.7%

Mainline Protestant

1.2%

Methodist

0.6%

Source · 2020 US Religion Census. Remaining 58.5% of residents not counted as adherents by any reporting body.

Once a bellwether of white working-class suburban politics, Contra Costa has shifted decisively leftward over three decades as the population diversified and Bay Area commuter culture extended eastward into its inland cities.

The Democratic margin in Contra Costa County has been steady. It reached its modern peak at forty-six points in 1936; the 2024 margin was thirty-eight points, still in line with the county's long pattern.

Contra Costa County's political identity is inseparable from its demographic profile: a 41% non-Hispanic-white share, a median household income of $127,229, and the full diversity of a major metropolitan center. The county's voting pattern resembles other major urban centers most closely — Montgomery County and Santa Clara County.

Most similar counties

Contra Costa County is one of the bluest places in America.