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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State directory

Illinois ZIP Codes

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

State ZIP Code City County Area Codes
IL 60437 Kinsman Grundy County 779, 815
IL 60438 Lansing Cook County 464, 708
IL 60439 Lemont Cook County 331, 464, 630, 708, 779, 815
IL 60440 Bolingbrook Will County 331, 630, 779, 815
IL 60441 Lockport Will County 331, 464, 630, 708, 779, 815
IL 60442 Manhattan Will County 464, 708, 779, 815
IL 60443 Matteson Cook County 464, 708
IL 60444 Mazon Grundy County 779, 815
IL 60445 Midlothian Cook County 464, 708
IL 60446 Romeoville Will County 331, 630, 779, 815
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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.