Mark DeSaulnier

Mark James DeSaulnier is an American politician who has served as a U.S. representative from California since 2015. He has represented the 10th congressional district since 2023, although it was previously numbered the 11th district for his first eight years in office. The district includes most of Contra Costa County, a suburban county in the East Bay. Until 2000, he was a member of the Republican Party; he has since been a member of the Democratic Party.