- illimitables
- Illinoian
- Illinois
- Illinois
- Illinois Benedictine College
- Illinois bundleflower
- Illinois Central College
- Illinois College
- Illinois Eastern Community College-Frontier
- Illinois Eastern Community College-Lincoln Trail
- Illinois Eastern Community College-Olney Central
- Illinois Eastern Community College-Wabash Valley
- Illinois Institute of Technology
- Illinois River
- Illinois State University
- Illinois Technical College
- Illinois Valley Community College
- Illinois Waterway
- Illinois Wesleyan University
- illiquid
- illiteracy
- illiterate
- illiterate
- ill-mannered
- ill nature