CA-4 · California

Congressional District CA-4 includes 54 indexable ZIP codes in California on US5, with a combined ZIP-area population of about 675,729.

Larger population clusters inside this district include Napa, CA, Davis, CA, Woodland, CA, Santa Rosa, CA, and Rohnert Park, CA. Open any ZIP below for full demographics, housing, schools, and nearby services.

The most populous ZIP currently listed for CA-4 is 94558 (about 64,552 residents).

Across ZIPs with income data in CA-4, the average median household income is about $95,817 — about 28% above the U.S. median ($75,149).

Average median home value across those ZIPs is about $666,711.

On this page’s income ranking, ZIP 94576 is near the top at about $165,625.

Congressional districts are the geographic units that elect members of the U.S. House of Representatives. District CA-4 is one of California's seats in the House; boundaries are redrawn after each decennial Census.

District lines are not the same as ZIP codes, cities, counties, area codes, or TV markets. A single ZIP can touch more than one district at the edges, and US5 maps each published ZIP to a primary district code for browseability.

US5 joins published ZIP profiles to congressional district codes so you can scan the district as a list of postal codes with population, income, and housing — then open any ZIP for maps, schools, commute, and climate context.

This is a place-based research view, not a voter roll, campaign tool, or live election results feed. Counts can change when geography publishes update.