Waterloo Mfg of Ontario – Canadian distributor of the Heider and Rock Island Tractor lines.
The following companies were closely tied to the Rock Island Plow Co with RIPC marketing their products either under the RIPC name or acting as partners with joint advertising that exceeded the normal jobber status.
Jacob Haish Mfg – Gas engines and Great Western products
Alamo Mfg – Gas engines
Joliet Mfg – Corn Shellers
Peoria Drill & Seeder- grain drills and endgate seeders