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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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Alameda County ZIP Codes

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

County State ZIP Code City Area Codes
Alameda County CA 94603 Oakland 341, 510
Alameda County CA 94604 Oakland 510
Alameda County CA 94605 Oakland 341, 510
Alameda County CA 94606 Oakland 341, 510
Alameda County CA 94607 Oakland 341, 415, 510, 628
Alameda County CA 94608 Emeryville 341, 510
Alameda County CA 94609 Oakland 341, 510
Alameda County CA 94610 Oakland 341, 510
Alameda County CA 94611 Oakland 341, 510, 925
Alameda County CA 94612 Oakland 341, 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.