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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Illinois ZIP Codes

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

State ZIP Code City County Area Codes
IL 60416 Coal City Grundy County 779, 815
IL 60417 Crete Will County 219, 464, 708
IL 60418 Crestwood Cook County 464, 708
IL 60419 Dolton Cook County 464, 708, 773, 872
IL 60420 Dwight Livingston County 779, 815
IL 60421 Elwood Will County 779, 815
IL 60422 Flossmoor Cook County 464, 708
IL 60423 Frankfort Will County 464, 708, 779, 815
IL 60424 Gardner Grundy County 779, 815
IL 60425 Glenwood Cook County 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.