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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 94505 Discovery Bay 209, 350, 925
Contra Costa County CA 94506 Danville 925
Contra Costa County CA 94507 Alamo 925
Contra Costa County CA 94509 Antioch 925
Contra Costa County CA 94511 Bethel Island 925
Contra Costa County CA 94513 Brentwood 209, 350, 925
Contra Costa County CA 94514 Byron 209, 350, 925
Contra Costa County CA 94516 Canyon 341, 510, 925
Contra Costa County CA 94517 Clayton 925
Contra Costa County CA 94518 Concord 925
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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.