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
All states and U.S. territories
Maps and coordinates
State directory

California ZIP Codes

Complete postal directory, details, and geographic map for the State of California.

State ZIP Code City County Area Codes
CA 94302 Palo Alto Santa Clara County 650
CA 94303 Palo Alto San Mateo County 650
CA 94304 Palo Alto Santa Clara County 650
CA 94305 Stanford Santa Clara County 650
CA 94306 Palo Alto Santa Clara County 650
CA 94309 Palo Alto Santa Clara County 650
CA 94401 San Mateo San Mateo County 650
CA 94402 San Mateo San Mateo County 650
CA 94403 San Mateo San Mateo County 650
CA 94404 San Mateo San Mateo County 650
Page 170 of 266

Geographic Map of California

Postal context

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.