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ZIP codes

ZIP codes in Lake County, Indiana

Lake County has 28 ZIP codes. 24 lie entirely inside it and 4 are shared with neighboring counties, so part of their land and their people are elsewhere. About 499,865 people live in the parts inside it (ACS 2020–2024).

By the All Map Tools Team

ZIP codes
28
With 1% or more of their land inside
Entirely inside
24
99% or more of their land
Shared with other counties
4
Most with Porter County (4)
Most populated ZIP
46307
71,673 people · Crown Point
Least populated ZIP
46377
45 people · Shelby
Largest ZIP by land
46356
113 sq mi · Lowell

Map of the ZIP codes in Lake County

Cook County, IL Kankakee County, IL Will County, IL Jasper County Newton County Porter County 46303 · Cedar Lake · 17,680 people · 100% in the county 46307 · Crown Point · 71,673 people · 97% in the county 46311 · Dyer · 23,321 people · 100% in the county 46312 · East Chicago · 26,022 people · 100% in the county 46319 · Griffith · 17,847 people · 100% in the county 46320 · Hammond · 14,353 people · 100% in the county 46321 · Munster · 23,733 people · 100% in the county 46322 · Highland · 23,680 people · 100% in the county 46323 · Hammond · 23,047 people · 100% in the county 46324 · Hammond · 21,409 people · 100% in the county 46327 · Hammond · 10,597 people · 100% in the county 46341 · Hebron · 10,048 people · 49% in the county 46342 · Hobart · 32,224 people · 72% in the county 46356 · Lowell · 19,721 people · 100% in the county 46373 · St. John · 18,843 people · 100% in the county 46375 · Schererville · 24,188 people · 100% in the county 46376 · Schneider · 319 people · 100% in the county 46377 · Shelby · 45 people · 100% in the county 46394 · Hammond · 11,894 people · 100% in the county 46402 · Gary · 5,836 people · 100% in the county 46403 · Gary · 10,929 people · 90% in the county 46404 · Gary · 15,428 people · 100% in the county 46405 · Lake Station · 12,184 people · 100% in the county 46406 · Gary · 9,001 people · 100% in the county 46407 · Gary · 8,577 people · 100% in the county 46408 · Gary · 15,747 people · 100% in the county 46409 · Gary · 7,184 people · 100% in the county 46410 · Merrillville · 39,243 people · 100% in the county
  • Entirely in the county (99% or more of its land)
  • Shared, mostly in this county
  • Shared, mostly in other counties
  • Neighboring counties
Open in the interactive tool

Each area is a ZIP code with its number where it fits. Hover over one to see its name.

All ZIP codes in Lake County

28 ZIP codes in Lake County, IN, by number
ZIP code Main city Population Land in the county Residents in the county
46303 Cedar Lake 17,680 100% 17,680
46307 Crown Point 71,673 97% ≈ 68,964
46311 Dyer 23,321 100% 23,321
46312 East Chicago 26,022 100% 26,022
46319 Griffith 17,847 100% 17,847
46320 Hammond 14,353 100% 14,353
46321 Munster 23,733 100% 23,733
46322 Highland 23,680 100% 23,680
46323 Hammond 23,047 100% 23,047
46324 Hammond 21,409 100% 21,409
46327 Hammond 10,597 100% 10,597
46341 Hebron 10,048 49% ≈ 2,153
46342 Hobart 32,224 72% ≈ 28,294
46356 Lowell 19,721 100% 19,721
46373 St. John 18,843 100% 18,843
46375 Schererville 24,188 100% 24,188
46376 Schneider 319 100% 319
46377 Shelby 45 100% 45
46394 Hammond 11,894 100% 11,894
46402 Gary 5,836 100% 5,836
46403 Gary 10,929 90% ≈ 10,555
46404 Gary 15,428 100% 15,428
46405 Lake Station 12,184 100% 12,184
46406 Gary 9,001 100% 9,001
46407 Gary 8,577 100% 8,577
46408 Gary 15,747 100% 15,747
46409 Gary 7,184 100% 7,184
46410 Merrillville 39,243 100% 39,243

ZIP codes shared with other counties

These 4 ZIP codes have part of their land in another county. The first figure is the share of their land in Lake County; then, where the rest lies.

Cities and prefixes

By main city (the city, town or CDP each ZIP shares the most land with), the ones with the most are Gary (7), Hammond (5), Cedar Lake (1), Crown Point (1), Dyer (1), and East Chicago (1); 18 places in all.

They start with 2 different three-digit prefixes, one per USPS sorting center: 463 and 464.

Neighboring counties

Each one with its ZIP codes. Those without a page of their own open in the tool.

Tools for this county

ZIP codes by county or city The same ZIP codes on an interactive map, with the list as CSV or to copy County map with cities Its cities, towns and CDPs with their population ZIP codes in a radius The ZIP codes within 10 miles of its center, or any distance you like

Sources

  • U.S. Census Bureau, 2020 ZCTA to County, ZCTA to Place and ZCTA to Census Tract Relationship Files (and the 2022 County Subdivision to ZCTA file for Connecticut). Public domain.
  • U.S. Census Bureau, American Community Survey 2020–2024 5-year estimates, table B01003 (population of each ZIP code, census tract and Connecticut town). Public domain.
  • U.S. Census Bureau, Vintage 2025 Population Estimates (county population) and 2025 Gazetteer Files (land area and interior point of each ZIP code). Public domain.
  • U.S. Census Bureau, Cartographic Boundary Files: ZCTAs 2020 and counties 2025, 1:500,000; county adjacency file 2025. Public domain.

How we count. ZIP codes here are the Census Bureau’s ZIP Code Tabulation Areas (ZCTAs), the areas it draws to match USPS ZIP codes; ZIPs with no area of their own (PO boxes, single buildings) aren’t included. A ZIP can cross county lines: “Land in the county” is the exact share of its land inside, from the Census relationship files. “Residents in the county” is the whole ZIP for those entirely inside; for shared ones it’s an estimate, spreading the people of each census tract over the land it shares with the ZIP. Population: ACS 2020–2024. Methodology.

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