California's 1st congressional district

California's 1st congressional district is a U.S. congressional district in California. The district is currently vacant following the death of Doug LaMalfa, a Republican, who had represented the district since January 2013. There will be a special election to fill the seat on August 4, 2026, with a primary election on June 2. If one candidate receives more than 50% of votes in the primary, the general election will be cancelled. Currently, the district encompasses many northeastern parts of the state. Since the 2022 election, it includes the counties of Butte, Colusa, Glenn, Lassen, Modoc, Shasta, Siskiyou, Sutter, and Tehama, and most of Yuba County. The largest cities in the district are Chico, Redding, and Yuba City.

Prior to redistricting in 2021, it included the counties of Butte, Lassen, Modoc, Plumas, Shasta, Sierra, Siskiyou, and Tehama, most of Nevada County, part of Glenn County, and part of Placer County. In the 2021 redistricting, it added the Yuba–Sutter area and removed most of its share of the Sierra Nevada.