Kamala D. Harris won Contra Costa County with 67.3% of the vote, ahead of Donald J. Trump. 528,904 votes were counted. The party margin was a Democratic lead of 37.9 points. Compared with the previous presidential election in Contra Costa County that is loaded, the margin moved 7.4 points toward Republicans.
Contra Costa County leans Democratic by 41.0 points compared with the nation (our partisan lean index, based on president 2024 75% + 2020 25%).
Contra Costa County voted for the winner of the national popular vote in 5 of 7 presidential elections from 2000 to 2024. On average its margin sat 34.4 points away from the national margin.
In 2024, 528,904 votes were cast in the biggest race, which is 67.1% of the 788,350 citizens aged 18 and over in Contra Costa County.
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