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 61032 Freeport Stephenson County 779, 815
IL 61036 Galena Jo Daviess County 563, 608, 779, 815
IL 61037 Galt Whiteside County 779, 815
IL 61038 Garden Prairie Boone County 779, 815
IL 61039 German Valley Stephenson County 779, 815
IL 61041 Hanover Jo Daviess County 563, 779, 815
IL 61042 Harmon Lee County 779, 815
IL 61043 Holcomb Ogle County 779, 815
IL 61044 Kent Stephenson County 779, 815
IL 61046 Lanark Carroll County 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.