| Name | What | Region | Country | Lat | Long | Elev ft. | Pop est |
|---|---|---|---|---|---|---|---|
| Ida B Wells Housing Project | city | Illinois | United States | 41.82 | -87.61 | 830 | |
| Ideal | city | Illinois | United States | 41.98 | -89.99 | 843 | |
| Idlewild | city | Illinois | United States | 42.35 | -87.99 | 830 | |
| Idlewood | city | Illinois | United States | 38.38 | -88.92 | 830 | |
| Idylside | city | Illinois | United States | 41.52 | -88.12 | 830 | |
| Iles | city | Illinois | United States | 39.77 | -89.65 | 830 | |
| Illiana | city | Illinois | United States | 40.20 | -87.53 | 830 | |
| Illiana (historical) | city | Illinois | United States | 39.80 | -87.53 | 830 | |
| Illiana Heights | city | Illinois | United States | 41.17 | -87.54 | 830 | |
| Illinois City | city | Illinois | United States | 41.40 | -90.90 | 830 | |
| Illinois Park | city | Illinois | United States | 42.05 | -88.31 | 830 | |
| Illiopolis | city | Illinois | United States | 39.85 | -89.24 | 830 | |
| Imbs | city | Illinois | United States | 38.52 | -90.14 | 413 | |
| Ina | city | Illinois | United States | 38.15 | -88.90 | 830 | |
| Independence | city | Illinois | United States | 39.53 | -90.79 | 830 | |
| Indian Boundary | city | Illinois | United States | 41.69 | -88.14 | 830 | |
| Indian Chase Meadows | city | Illinois | United States | 41.69 | -88.14 | 830 | |
| Indian Creek | city | Illinois | United States | 42.23 | -87.98 | 830 | |
| Indian Creek | city | Illinois | United States | 41.95 | -88.48 | 948 | |
| Indian Creek Country Estates | city | Illinois | United States | 42.23 | -88.04 | 830 | |
| Indian Head Park | city | Illinois | United States | 41.77 | -87.90 | 830 | |
| Indian Hill | city | Illinois | United States | 41.50 | -87.65 | 830 | |
| Indian Oaks | city | Illinois | United States | 41.19 | -87.85 | 830 | |
| Indian Oaks | city | Illinois | United States | 41.70 | -88.08 | 830 | |
| Indian Ridge | city | Illinois | United States | 42.10 | -87.86 | 830 | |
| Indian Spring | city | Illinois | United States | 41.18 | -89.36 | 830 | |
| Indian Trails | city | Illinois | United States | 42.25 | -88.63 | 898 | |
| Indian Village | city | Illinois | United States | 42.23 | -89.11 | 830 | |
| Indianola | city | Illinois | United States | 39.93 | -87.74 | 830 | |
| Industry | city | Illinois | United States | 40.33 | -90.61 | 830 | |
| Ingalls Park | city | Illinois | United States | 41.52 | -88.04 | 830 | |
| Ingalton | city | Illinois | United States | 41.91 | -88.20 | 830 | |
| Ingleside | city | Illinois | United States | 42.38 | -88.14 | 830 | |
| Ingleside Shore | city | Illinois | United States | 42.40 | -88.14 | 830 | |
| Ingraham | city | Illinois | United States | 38.84 | -88.33 | 830 | |
| Inlet | city | Illinois | United States | 41.74 | -89.24 | 830 | |
| Inman | city | Illinois | United States | 37.84 | -88.17 | 377 | |
| Innisfail | city | Illinois | United States | 42.13 | -87.85 | 830 | |
| Inverness | city | Illinois | United States | 42.12 | -88.10 | 830 | |
| Iola | city | Illinois | United States | 38.83 | -88.63 | 830 | |
| Iowa Junction | city | Illinois | United States | 40.69 | -91.06 | 830 | |
| Ipava | city | Illinois | United States | 40.35 | -90.32 | 830 | |
| Irene | city | Illinois | United States | 42.17 | -88.90 | 830 | |
| Iron | city | Illinois | United States | 37.97 | -88.24 | 830 | |
| Irondale | city | Illinois | United States | 41.71 | -87.55 | 830 | |
| Irondale (historical) | city | Illinois | United States | 41.70 | -87.54 | 830 | |
| Ironworkers Addition to South Chicago | city | Illinois | United States | 41.71 | -87.54 | 830 | |
| Iroquois | city | Illinois | United States | 40.83 | -87.58 | 830 | |
| Irving | city | Illinois | United States | 39.21 | -89.40 | 830 | |
| Irving Park | city | Illinois | United States | 41.95 | -87.74 | 830 | |
| Irvington | city | Illinois | United States | 38.44 | -89.16 | 830 | |
| Irwin | city | Illinois | United States | 41.05 | -87.98 | 830 | |
| Irwins Park | city | Illinois | United States | 39.63 | -89.73 | 830 | |
| Isabel | city | Illinois | United States | 39.66 | -87.95 | 830 | |
| Island Grove | city | Illinois | United States | 39.72 | -89.96 | 830 | |
| Island Grove | city | Illinois | United States | 39.10 | -88.34 | 830 | |
| Island Lake | city | Illinois | United States | 42.28 | -88.19 | 830 | |
| Island View | city | Illinois | United States | 39.21 | -89.62 | 830 | |
| Italian Bowery | city | Illinois | United States | 41.75 | -87.60 | 830 | |
| Itasca | city | Illinois | United States | 41.98 | -88.01 | 830 | |
| Iuka | city | Illinois | United States | 38.62 | -88.79 | 830 | |
| Ivanhoe | city | Illinois | United States | 42.28 | -88.04 | 830 | |
| Ivanhoe | city | Illinois | United States | 41.71 | -88.06 | 830 | |
| Ivesdale | city | Illinois | United States | 39.94 | -88.46 | 830 | |
| Ivy | city | Illinois | United States | 38.15 | -90.23 | 383 | |
| Ivy Club of Northbrook | city | Illinois | United States | 42.15 | -87.89 | 830 | |
| Ivy Heights | city | Illinois | United States | 38.86 | -90.06 | 830 |