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 61018 Dakota Stephenson County 779, 815
IL 61019 Davis Stephenson County 608, 779, 815
IL 61020 Davis Junction Ogle County 779, 815
IL 61021 Dixon Lee County 779, 815
IL 61024 Durand Winnebago County 608, 779, 815
IL 61025 East Dubuque Jo Daviess County 563, 608, 779, 815
IL 61027 Eleroy Stephenson County 779, 815
IL 61028 Elizabeth Jo Daviess County 779, 815
IL 61030 Forreston Ogle County 779, 815
IL 61031 Franklin Grove Lee 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.