Identifiers: city · town · CDP
| Rank | Community | Population |
|---|---|---|
| 1 | Hammond (city), IN | 77,879 |
| 2 | Gary (city), IN | 69,093 |
| 3 | Portage (city), IN | 37,926 |
| 4 | Merrillville (town), IN | 36,444 |
| 5 | Valparaiso (city), IN | 34,151 |
| 6 | Crown Point (city), IN | 33,899 |
| 7 | Hobart (city), IN | 29,752 |
| 8 | Schererville (town), IN | 29,646 |
| 9 | East Chicago (city), IN | 26,370 |
| 10 | Highland (town), IN | 23,984 |
| 11 | Munster (town), IN | 23,894 |
| 12 | St. John (town), IN | 20,303 |
| 13 | Griffith (town), IN | 16,528 |
| 14 | Dyer (town), IN | 16,517 |
| 15 | Chesterton (town), IN | 14,241 |
| 16 | Cedar Lake (town), IN | 14,106 |
| 17 | Lake Station (city), IN | 13,235 |
| 18 | Lowell (town), IN | 10,680 |
| 19 | Winfield (town), IN | 7,181 |
| 20 | Lakes of the Four Seasons (CDP), IN | 7,091 |