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 61006 Ashton Lee County 779, 815
IL 61007 Baileyville Ogle County 779, 815
IL 61008 Belvidere Boone County 779, 815
IL 61010 Byron Ogle County 779, 815
IL 61011 Caledonia Boone County 779, 815
IL 61012 Capron Boone County 779, 815
IL 61013 Cedarville Stephenson County 779, 815
IL 61014 Chadwick Carroll County 779, 815
IL 61015 Chana Ogle County 779, 815
IL 61016 Cherry Valley Winnebago 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.