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 62277 Prairie Du Rocher Randolph County 573, 618
IL 62278 Red Bud Randolph County 618
IL 62279 Renault Monroe County 618
IL 62280 Rockwood Randolph County 573, 618
IL 62281 Saint Jacob Madison County 618
IL 62282 Saint Libory St. Clair County 618
IL 62284 Smithboro Bond County 618
IL 62285 Smithton St. Clair County 618
IL 62286 Sparta Randolph County 618
IL 62288 Steeleville Randolph County 618
Page 114 of 159

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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.