California's 4th Congressional District
California · CA-04
California's 4th Congressional District is one of 52 U.S. House districts in California, represented in Congress by Mike Thompson (Democrat). It is home to roughly 756,454 people, with a median age of 38. The population is about 51% White. The median household income is $93,155, and 33% of adults 25 and older hold a bachelor’s degree or higher. In the 2024 presidential election it voted safely Democratic (D+31).
Representative
Current U.S. House member (source: house.gov).
Geography
CA-04 is shown in red. Click a neighboring district to open it, or zoom out to explore the country.
Covering 4,929 square miles, CA-04 is the 147th-largest of the 435 congressional districts by land area. With about 153 residents per square mile, it is a mix of small cities, suburbs and countryside. Its shape is irregular: the district's Polsby-Popper score of 0.20 ranks 320th of 435 nationally, where 1st is the most compact.
Presidential results
In the 2024 presidential election, 64% of CA-04 voters backed Kamala Harris and 33% Donald Trump — a D+31 margin. That is a 6.0-point shift toward the Republicans from 2020, when the district voted D+37.
Two-party presidential vote by district (source: The Downballot).
Who lives here
The median resident of the district is 38 years old; 21.8% of residents are under 18 and 17.6% are 65 or older. About 18.7% of residents were born outside the United States, and 31% speak a language other than English at home.
U.S. Census Bureau, American Community Survey (5-year estimates).
Economy & education
At $93,155, the district's median household income ranks 107th of 435 districts nationwide. The typical owner-occupied home is worth $604,362, and the median rent is $1,781 a month. 11.9% of residents live below the poverty line, and workers average a 28.8-minute commute (13.1% work from home).
U.S. Census Bureau, American Community Survey (5-year estimates).