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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.

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Contra Costa County ZIP Codes

Browse all ZIP Codes, cities, and associated area codes registered in Contra Costa County.

County State ZIP Code City Area Codes
Contra Costa County CA 94597 Walnut Creek 925
Contra Costa County CA 94598 Walnut Creek 925
Contra Costa County CA 94801 Richmond 341, 415, 510, 628
Contra Costa County CA 94802 Richmond 510
Contra Costa County CA 94803 El Sobrante 341, 510, 925
Contra Costa County CA 94804 Richmond 341, 510
Contra Costa County CA 94805 Richmond 341, 510
Contra Costa County CA 94806 San Pablo 341, 510
Contra Costa County CA 94807 Richmond 510
Contra Costa County CA 94808 Richmond 510
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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.