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 60428 Markham 464, 708
Cook County IL 60429 Hazel Crest 464, 708
Cook County IL 60430 Homewood 464, 708
Cook County IL 60438 Lansing 464, 708
Cook County IL 60439 Lemont 331, 464, 630, 708, 779, 815
Cook County IL 60443 Matteson 464, 708
Cook County IL 60445 Midlothian 464, 708
Cook County IL 60452 Oak Forest 464, 708
Cook County IL 60453 Oak Lawn 464, 708, 773, 872
Cook County IL 60454 Oak Lawn 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.