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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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San Mateo County ZIP Codes

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

County State ZIP Code City Area Codes
San Mateo County CA 94080 South San Francisco 415, 628, 650
San Mateo County CA 94083 South San Francisco 650
San Mateo County CA 94128 San Francisco 650
San Mateo County CA 94303 Palo Alto 650
San Mateo County CA 94401 San Mateo 650
San Mateo County CA 94402 San Mateo 650
San Mateo County CA 94403 San Mateo 650
San Mateo County CA 94404 San Mateo 650
San Mateo County CA 94497 San Mateo 650
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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.