According to the Geographic Names Information System, the Iroquois River, or portions thereof, has also been known as:[2] The name, La rivière des Iroquois was given to the riverway by the French, through the Annual of René de la Salle.

[4] The French explores had arrived in the Kankakee basin René-Robert Cavelier, Sieur de La Salle in 1679.

In 1682 he built Fort St. Louis atop Starved Rock State Park on the Illinois River as a place of refuge from raiding Iroquois.

[4] A legend among the Illinois tells of a time the Iroquois were surprised along the bank of this waterway and were driven away with great losses.

[5] The Iroquois river is fed by the Sugar, Mud, Fountain Spring, Prairie, Langham, Pike and Beaver creeks.