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 94928 Rohnert Park Sonoma County 707
CA 94929 Dillon Beach Marin County 707
CA 94930 Fairfax Marin County 415, 628
CA 94931 Cotati Sonoma County 707
CA 94933 Forest Knolls Marin County 415, 628
CA 94937 Inverness Marin County 415, 628, 707
CA 94938 Lagunitas Marin County 415, 628
CA 94939 Larkspur Marin County 415, 628
CA 94940 Marshall Marin County 415, 628, 707
CA 94941 Mill Valley Marin County 415, 628
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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.