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
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Cook County ZIP Codes

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

County State ZIP Code City Area Codes
Cook County IL 60601 Chicago 312, 872
Cook County IL 60602 Chicago 312, 872
Cook County IL 60603 Chicago 312, 872
Cook County IL 60604 Chicago 312, 872
Cook County IL 60605 Chicago 312, 872
Cook County IL 60606 Chicago 312, 872
Cook County IL 60607 Chicago 312, 872
Cook County IL 60608 Chicago 312, 773, 872
Cook County IL 60609 Chicago 312, 773, 872
Cook County IL 60610 Chicago 312, 872
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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.