ZIP codes in Lake County

33 ZIPs touch Lake County, Indiana. The blue dashed line is the county border; orange ZIPs reach into it.

ZIP codes

cross the county line

514,773

people in these ZIPs

counties in IN

Most people

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Lake County ZIP list

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All 92 counties in Indiana

Questions people actually ask

How many ZIP codes are in Lake County, Indiana?

33 ZIP codes reach into Lake County, including 5 PO Box or single-address ZIPs placed by the town they serve. 4 of them are only partly in the county and also cover a neighboring county.

Which ZIP code in Lake County has the most people?

46307 (Crown Point) has about 71,673 residents, the most of any ZIP touching Lake County, in the Census Bureau’s ACS 2020–2024 estimates.

Can a ZIP code be in Lake County and another county?

Yes. ZIP codes follow mail routes, not county lines. Rows marked with a percentage show how much of that ZIP’s land is in Lake County. For one address, pin the exact spot on the ZIP finder to see its county.

Where does this list come from?

ZIP areas and their county overlaps come from the Census Bureau’s 2020 ZIP Code Tabulation Area to county relationship file. PO Box ZIPs have no area, so each is placed in the county of the ZIP area nearest the town it serves.

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Updated 2026-11-10 · Where the data comes from