California's 4th congressional district (CA-04)
California's 4th congressional district (CA-04) covers parts or all of 9 counties, including Colusa County, Napa County, Sutter County, Yuba County, Yolo County and Sonoma County, and 91 ZIP codes (55 wholly inside it). Its 2020 population was 758,116. This is the map in force for the November 3, 2026 election.
Who represents CA-04
| Office | Member | Contact |
|---|---|---|
| U.S. Representative (CA-04) | Mike Thompson (D) | 202-225-3311 |
| U.S. Senator | Adam B. Schiff (D) | 202-224-3841 |
| U.S. Senator | Alex Padilla (D) | 202-224-3553 · contact form |
Elected in 2024 under CA's previous congressional map; this district's lines changed for the 120th Congress (seated January 3, 2027).
Officials serving now (members of Congress until January 3, 2027). Sources: Members of Congress: the @unitedstates project, congress-legislators (CC0).
Counties
| County | Share of the county's residents in CA-04 |
|---|---|
| Colusa County | 100% |
| Napa County | 100% |
| Sutter County | 100% |
| Yuba County | 100% |
| Yolo County | 68% |
| Sonoma County | 31% |
| Placer County | 15% |
| Lake County | 8.9% |
| Sacramento County | 3.2% |
ZIP codes
Percentages mark ZIPs only partly in CA-04: the share of that ZIP's residents inside it.
- 94503 (100%)
- 94508
- 94515 (99%)
- 94558
- 94559
- 94562
- 94567
- 94573
- 94574
- 94576
- 94591 (<0.1%)
- 94599
- 94928
- 94931 (100%)
- 94951
- 94952 (0.3%)
- 94954
- 95404 (9.8%)
- 95407 (22%)
- 95409 (2.8%)
- 95422 (0.1%)
- 95423 (0.2%)
- 95426 (19%)
- 95431
- 95442
- 95452
- 95457 (51%)
- 95461 (80%)
- 95467 (31%)
- 95472 (0.9%)
- 95476
- 95606
- 95607
- 95616
- 95618 (51%)
- 95626
- 95627
- 95637
- 95645
- 95648 (98%)
- 95653
- 95659
- 95660 (0.2%)
- 95668
- 95673 (99%)
- 95674
- 95676
- 95679
- 95681
- 95691 (0.3%)
- 95692
- 95694 (88%)
- 95695
- 95697
- 95698
- 95747 (7.9%)
- 95765 (<0.1%)
- 95776
- 95837 (83%)
- 95843 (59%)
- 95901 (99%)
- 95903
- 95912
- 95914 (17%)
- 95918
- 95919
- 95922 (99%)
- 95925
- 95930 (9.5%)
- 95932
- 95935
- 95937
- 95941 (24%)
- 95948 (0.2%)
- 95950
- 95953
- 95955
- 95957
- 95960 (6.0%)
- 95961
- 95962
- 95966 (0.4%)
- 95970 (64%)
- 95972
- 95977 (41%)
- 95979
- 95981 (50%)
- 95982
- 95987
- 95991
- 95993
Towns
Angwin CCD, Calistoga CCD, Central Colusa CCD, East Colusa CCD, East Yuba-Beale AFB CCD, Esparto CCD, Knights Landing CCD, Lake Berryessa CCD, Linda CCD, Live Oak CCD, Marysville CCD, Marysville Northeast CCD, Meridian-Robbins CCD, Napa CCD, Olivehurst CCD, Sonoma CCD, South Sutter CCD, St. Helena CCD, Sutter CCD, West Colusa CCD, Wheatland CCD, Winters CCD, Woodland CCD, Yuba City CCD, Yuba City Southwest CCD, Yuba Foothills CCD, Davis CCD, Petaluma CCD, Lincoln CCD, Middletown CCD, Lower Lake CCD, Cobb CCD, Santa Rosa CCD, Roseville CCD, Sacramento CCD, Sebastopol CCD, Cloverdale-Geyserville CCD, East Yolo CCD, Clearlake CCD and Rocklin CCD.
Get this in your AI agent
Your agent can draw every precinct in CA-04, or list them with population shares (related_geographies). Add https://boundarymcp.com/mcp to Claude, ChatGPT, Cursor or Codex (free, no key; how), then:
get_boundaries(id="us:congressional_district:0604", children_level="precinct", include_districts=True)