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 61234 Annawan Henry County 309, 779, 815
IL 61235 Atkinson Henry County 309
IL 61236 Barstow Rock Island County 309
IL 61237 Buffalo Prairie Rock Island County 309
IL 61238 Cambridge Henry County 309
IL 61239 Carbon Cliff Rock Island County 309
IL 61240 Coal Valley Rock Island County 309
IL 61241 Colona Henry County 309
IL 61242 Cordova Rock Island County 309, 563
IL 61243 Deer Grove Whiteside 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.