| Name | What | Region | Country | Lat | Long | Elev Ft. | Pop Est |
|---|
| Ida B Wells Housing Project subdivision | city | Illinois | United States | 41.82444 | -87.61333 | 587 | 387164 |
| Ideal | city | Illinois | United States | 41.975 | -89.98806 | 843 | 1228 |
| Idlewild | city | Illinois | United States | 42.35306 | -87.99278 | 797 | 36478 |
| Idlewood | city | Illinois | United States | 38.38028 | -88.92278 | 547 | 7386 |
| Idylside | city | Illinois | United States | 41.51889 | -88.12194 | 636 | 101970 |
| Iles | city | Illinois | United States | 39.77139 | -89.65361 | 600 | 102372 |
| Illiana | city | Illinois | United States | 40.19639 | -87.53194 | 711 | 4909 |
| Illiana Heights | city | Illinois | United States | 41.16889 | -87.54306 | 629 | 3109 |
| Illiana historical | city | Illinois | United States | 39.80361 | -87.53333 | 636 | 989 |
| Illinois City | city | Illinois | United States | 41.3975 | -90.89944 | 754 | 1112 |
| Illinois Park subdivision | city | Illinois | United States | 42.04806 | -88.31417 | 807 | 84889 |
| Illiopolis | city | Illinois | United States | 39.85361 | -89.24194 | 600 | 1461 |
| Imbs | city | Illinois | United States | 38.52361 | -90.13528 | 413 | 21914 |
| Ina | city | Illinois | United States | 38.15111 | -88.90389 | 439 | 1692 |
| Independence | city | Illinois | United States | 39.53139 | -90.79139 | 639 | 600 |
| Indian Creek | city | Illinois | United States | 42.22694 | -87.97972 | 741 | 71775 |
| Indian Head Park | city | Illinois | United States | 41.77028 | -87.90222 | 659 | 106808 |
| Indian Hill | city | Illinois | United States | 41.50167 | -87.64778 | 675 | 111875 |
| Indian Oaks | city | Illinois | United States | 41.19167 | -87.85139 | 692 | 27900 |
| Indian Spring | city | Illinois | United States | 41.18111 | -89.36028 | 439 | 1942 |
| Indian Village subdivision | city | Illinois | United States | 42.22972 | -89.10639 | 698 | 79535 |
| Indianola | city | Illinois | United States | 39.92722 | -87.74 | 675 | 1510 |
| Industry | city | Illinois | United States | 40.32778 | -90.60694 | 659 | 604 |
| Ingalls Park | city | Illinois | United States | 41.5225 | -88.04278 | 613 | 93703 |
| Ingalton | city | Illinois | United States | 41.90611 | -88.20361 | 787 | 70411 |
| Ingleside | city | Illinois | United States | 42.38111 | -88.13972 | 777 | 36868 |
| Ingleside Shore | city | Illinois | United States | 42.40167 | -88.14417 | 744 | 36868 |
| Ingraham | city | Illinois | United States | 38.83611 | -88.33389 | 469 | 695 |
| Inlet | city | Illinois | United States | 41.735 | -89.24028 | 754 | 1060 |
| Inman | city | Illinois | United States | 37.83778 | -88.17306 | 377 | 824 |
| Inverness | city | Illinois | United States | 42.11806 | -88.09611 | 836 | 82708 |
| Iola | city | Illinois | United States | 38.83444 | -88.62806 | 508 | 772 |
| Iowa Junction | city | Illinois | United States | 40.68722 | -91.06 | 567 | 875 |
| Ipava | city | Illinois | United States | 40.35139 | -90.32444 | 646 | 719 |
| Irene | city | Illinois | United States | 42.17028 | -88.90028 | 803 | 5728 |
| Iron | city | Illinois | United States | 37.97389 | -88.24139 | 449 | 920 |
| Irondale historical | city | Illinois | United States | 41.69583 | -87.54028 | 583 | 107356 |
| Irondale subdivision | city | Illinois | United States | 41.71056 | -87.55222 | 577 | 276055 |
| Ironworkers Addition to South Chicago subdivision | city | Illinois | United States | 41.7075 | -87.53639 | 583 | 107356 |
| Iroquois | city | Illinois | United States | 40.8275 | -87.58194 | 649 | 1313 |
| Irving | city | Illinois | United States | 39.20583 | -89.40444 | 659 | 1837 |
| Irving Park subdivision | city | Illinois | United States | 41.95333 | -87.73639 | 603 | 722202 |
| Irvington | city | Illinois | United States | 38.43917 | -89.16278 | 541 | 2454 |
| Irwin | city | Illinois | United States | 41.05222 | -87.98389 | 649 | 3321 |
| Irwins Park | city | Illinois | United States | 39.62611 | -89.72611 | 613 | 6060 |
| Isabel | city | Illinois | United States | 39.65528 | -87.95 | 652 | 605 |
| Island Grove | city | Illinois | United States | 39.72417 | -89.96083 | 659 | 1107 |
| Island Grove | city | Illinois | United States | 39.1025 | -88.33528 | 600 | 1583 |
| Island Lake | city | Illinois | United States | 42.27611 | -88.19194 | 757 | 30052 |
| Island View | city | Illinois | United States | 39.21056 | -89.61528 | 643 | 4229 |
| Italian Bowery subdivision | city | Illinois | United States | 41.75472 | -87.59861 | 587 | 501001 |
| Itasca | city | Illinois | United States | 41.975 | -88.00722 | 698 | 118069 |
| Iuka | city | Illinois | United States | 38.61611 | -88.79028 | 518 | 1329 |
| Ivanhoe | city | Illinois | United States | 42.27889 | -88.04194 | 800 | 25676 |
| Ivesdale | city | Illinois | United States | 39.94333 | -88.45528 | 675 | 1725 |
| Ivy | city | Illinois | United States | 38.15139 | -90.23417 | 383 | 1482 |
| Ivy Heights | city | Illinois | United States | 38.86222 | -90.05722 | 479 | 36085 |