27 zips
| Zip Code | City | Population ↓ |
|---|---|---|
| 46307 | Crown Point | 71,355 |
| 46410 | Merrillville | 39,121 |
| 46342 | Hobart | 32,049 |
| 46312 | East Chicago | 26,363 |
| 46322 | Highland | 23,794 |
| 46375 | Schererville | 23,740 |
| 46321 | Munster | 23,731 |
| 46323 | Hammond | 23,447 |
| 46311 | Dyer | 23,074 |
| 46324 | Hammond | 21,703 |
| 46356 | Lowell | 18,814 |
| 46373 | Saint John | 17,741 |
| 46319 | Griffith | 17,626 |
| 46303 | Cedar Lake | 16,859 |
| 46404 | Gary | 16,851 |
| 46408 | Gary | 15,368 |
| 46320 | Hammond | 13,822 |
| 46394 | Whiting | 12,117 |
| 46405 | Lake Station | 11,547 |
| 46403 | Gary | 10,875 |
| 46327 | Hammond | 10,875 |
| 46407 | Gary | 9,125 |
| 46406 | Gary | 8,730 |
| 46409 | Gary | 7,050 |
| 46402 | Gary | 5,873 |
| 46376 | Schneider | 204 |
| 46377 | Shelby | 66 |
The data shown reflect ZCTAs from the US Census. As of 2024, there are 27 ZCTAs in Lake County, Indiana (US Census).