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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Illinois ZIP Codes

Complete postal directory, details, and geographic map for the State of Illinois.

State ZIP Code City County Area Codes
IL 61275 Port Byron Rock Island County 309, 563
IL 61276 Preemption Mercer County 309
IL 61277 Prophetstown Whiteside County 309, 779, 815
IL 61278 Rapids City Rock Island County 309, 563
IL 61279 Reynolds Rock Island County 309
IL 61281 Sherrard Mercer County 309
IL 61282 Silvis Rock Island County 309
IL 61283 Tampico Whiteside County 779, 815
IL 61284 Taylor Ridge Rock Island County 309
IL 61285 Thomson Carroll County 563, 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.