California·CA·FIPS 06013

Contra Costa County

Voted Democratic in 2024 · 528,904 votes cast

About Contra Costa County

Contra Costa County is a county located in the U.S. state of California, in the East Bay of the San Francisco Bay Area. As of the 2020 United States census, the population was 1,165,927. The county seat is Martinez. It occupies the northern portion of the East Bay region of the San Francisco Bay Area and is primarily suburban. The county's name refers to its position on the other side of the bay from San Francisco. Contra Costa County is included in the San Francisco–Oakland–Berkeley, CA Metropolitan Statistical Area.

2024 Presidential Results

All candidates · Contra Costa County, California

Kamala D Harris(Democrat)

67.3%356,008

Won by 200,700 votes

Donald J Trump(Republican)

29.4%155,308

Other(Other)

2.9%15,232

Chase Oliver(Libertarian)

0.4%2,356

Margin History

Red = Republican, Blue = Democratic

2024D+37.9

2020D+45.3

2016D+43.6

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Swung Right in 2024

Contra Costa County shifted 7.4 points toward Republicans compared to 2020. Voter turnout decreased by 9.0%.

Contra Costa County — Local Discussion

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What does Contra Costa County really think?

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Election data: MIT Election Data Science Lab, Harvard Dataverse (CC BY 4.0)