The Illiniwek was a confederation of many Native American subtribes in the upper Missippippi Valley of North America. The five most populous tribes were the Kaskaskia, the Cahokia, the Peoria, the Tamaroa, and the Michigamea.

When French explorers first journeyed to the region from Canada in the early 17th Century, they found the area inhabited by a vigorous, populous Algonquin nation who called themselves "Hileni" or "Illiniwek" which means "men." This the French rendered as "Illinois". Today most people know little about this once powerful confederation of tribes.