I
- Ideal
- Idlewood
- Idylside
- Illinoi
- Illinois City
- Illiopolis
- Imbs
- Ina
- Independence
- Indian Creek
- Indian Head Park
- Indian Oaks
- Indianola
- Indian Point
- Indian Spring
- Industry
- Ingalls Park
- Ingalton
- Ingraham
- Inlet
- Inman
- Inverness
- Iola
- Ipava
- Irene
- Iron
- Iroquois
- Irving
- Irvington
- Irwin
- Irwins Park
- Isabel
- Island Grove
- Island Grove
- Island Lake
- Island View
- Itasca
- Iuka
- Ivanhoe
- Ivesdale
- Ivy
- Ivy Heights