City | 2024 Population |
|---|---|
| Illini | 1,288 |
| Illinois City | 16 |
| Illiopolis | 834 |
| Ina | 1,660 |
| Independence | 1,133 |
| Indian Creek | 528 |
| Indian Grove | 4,073 |
| Indian Head Park | 3,813 |
| Indian Point | 1,364 |
| Indian Prairie | 657 |
| Indianola | 219 |
| Indiantown | 580 |
| Industry | 388 |
| Ingalls Park | 3,182 |
| Inverness | 7,139 |
| Iola | 95 |
| Ipava | 423 |
| Irishtown | 1,054 |
| Iroquois | 128 |
| Irving | 367 |
| Irvington | 568 |
| Irwin | 66 |
| Isabel | 174 |
| Island Grove | 558 |
| Island Lake | 7,875 |
| Itasca | 9,203 |
| Iuka | 485 |
| Ivesdale | 250 |