California's 21st Congressional District
California · CA-21
California's 21st Congressional District is one of 52 U.S. House districts in California, represented in Congress by Jim Costa (Democrat). It is home to roughly 781,192 people, with a median age of 32. The population is about 62% Hispanic. The median household income is $61,529, and 17% of adults 25 and older hold a bachelor’s degree or higher. In the 2024 presidential election the district was highly competitive (D+4).
Representative
Current U.S. House member (source: house.gov).
Geography
CA-21 is shown in red. Click a neighboring district to open it, or zoom out to explore the country.
Covering 653 square miles, CA-21 is the 305th-largest of the 435 congressional districts by land area. With about 1,196 residents per square mile, it is a largely suburban district. Its shape is very irregular: the district's Polsby-Popper score of 0.18 ranks 341st of 435 nationally, where 1st is the most compact.
Presidential results
In the 2024 presidential election, 51% of CA-21 voters backed Kamala Harris and 47% Donald Trump — a D+4 margin, the 32nd-closest result of any district in the country. That is a 16.0-point shift toward the Republicans from 2020, when the district voted D+20.
Two-party presidential vote by district (source: The Downballot).
Who lives here
The median resident of the district is 32 years old, making this one of the youngest districts in the nation by median age; 29% of residents are under 18 and 11.8% are 65 or older. About 20.5% of residents were born outside the United States, and 49% speak a language other than English at home.
U.S. Census Bureau, American Community Survey (5-year estimates).
Economy & education
At $61,529, the district's median household income ranks 378th of 435 districts nationwide. The typical owner-occupied home is worth $307,922, and the median rent is $1,219 a month. 22% of residents live below the poverty line, and workers average a 24.2-minute commute (8.3% work from home).
U.S. Census Bureau, American Community Survey (5-year estimates).