D
- Dawn Equipment Company (Sycamore, Illinois)
- DAXCON Engineering, Inc. (Bartonville, Illinois)
- Deere & Company (Moline, Illinois)
- DEKALB Genetics Corporation (DeKalb, Illinois)
- Detonics (Millstadt, Illinois)
- Dot Foods (Mount Sterling, Illinois)
Read more about this topic: List Of Illinois Companies