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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.

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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 IN 46321 Munster 219, 464, 708
Lake County IN 46322 Highland 219
Lake County IN 46323 Hammond 219
Lake County IN 46324 Hammond 219, 464, 708
Lake County IN 46325 Hammond 219
Lake County IN 46327 Hammond 219, 464, 708, 773, 872
Lake County IN 46342 Hobart 219
Lake County IN 46355 Leroy 219
Lake County IN 46356 Lowell 219, 779, 815
Lake County IN 46373 Saint John 219
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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.