U.S. postal lookup

U.S. ZIP Codes Database 2026

Search by ZIP code, city, county, or state and find clear postal details with maps, time zones, and area code data.

42,735 verified records
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California ZIP Codes

Complete postal directory, details, and geographic map for the State of California.

State ZIP Code City County Area Codes
CA 94497 San Mateo San Mateo County 650
CA 94501 Alameda Alameda County 341, 415, 510, 628
CA 94502 Alameda Alameda County 341, 510
CA 94503 American Canyon Napa County 707
CA 94505 Discovery Bay Contra Costa County 209, 350, 925
CA 94506 Danville Contra Costa County 925
CA 94507 Alamo Contra Costa County 925
CA 94508 Angwin Napa County 707
CA 94509 Antioch Contra Costa County 925
CA 94510 Benicia Solano County 707
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About U.S. ZIP Codes

ZIP codes are a United States Postal Service system introduced in 1963 to make mail routing more accurate and efficient. The standard format uses five digits, while ZIP+4 adds four more digits for a more precise delivery segment.

ZIP codes cover the United States, its territories, military mail routes, and other USPS delivery points. This directory organizes that data for practical lookup by ZIP code, city, county, and state.