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 62421 Claremont Richland County 618
IL 62422 Cowden Shelby County 217, 447, 618
IL 62423 Dennison Clark County 217, 447, 812, 930
IL 62424 Dieterich Effingham County 217, 447, 618
IL 62425 Dundas Richland County 618
IL 62426 Edgewood Effingham County 618
IL 62427 Flat Rock Crawford County 618, 812, 930
IL 62428 Greenup Cumberland County 217, 447, 618
IL 62431 Herrick Shelby County 217, 447, 618
IL 62432 Hidalgo Jasper County 217, 447, 618
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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.