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.

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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 60406 Blue Island 464, 708, 773, 872
Cook County IL 60409 Calumet City 464, 708, 773, 872
Cook County IL 60411 Chicago Heights 219, 464, 708
Cook County IL 60412 Chicago Heights 708
Cook County IL 60415 Chicago Ridge 464, 708
Cook County IL 60418 Crestwood 464, 708
Cook County IL 60419 Dolton 464, 708, 773, 872
Cook County IL 60422 Flossmoor 464, 708
Cook County IL 60425 Glenwood 464, 708
Cook County IL 60426 Harvey 464, 708
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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.