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
All states and U.S. territories
Maps and coordinates
County directory

Lake County ZIP Codes

Browse all ZIP Codes, cities, and associated area codes registered in Lake County.

County State ZIP Code City Area Codes
Lake County IL 60092 Libertyville 224
Lake County IL 60096 Winthrop Harbor 224, 262, 847
Lake County IL 60099 Zion 224, 262, 847
Lake County IN 46303 Cedar Lake 219, 464, 708
Lake County IN 46307 Crown Point 219
Lake County IN 46308 Crown Point 219
Lake County IN 46311 Dyer 219, 464, 708
Lake County IN 46312 East Chicago 219
Lake County IN 46319 Griffith 219
Lake County IN 46320 Hammond 219, 464, 708
Page 10 of 27

Geographic Map of Lake County

Postal context

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.