The Kaskaskia were one of the indigenous peoples of the Northeastern Woodlands. They were one of about a dozen cognate tribes that made up the Illiniwek Confederation, also called the Illinois Confederation. Their longstanding homeland was in the Great Lakes region. Their first contact with Europeans reportedly occurred near present-day Green Bay, Wisconsin, in 1667 at a Jesuit mission station.

In 1673, Jesuit Father Jacques Marquette and French-Canadian explorer Louis Jolliet became the first Europeans known to have descended the Mississippi River. The record of their trip is the earliest, best record of contact between Europeans and the Illinois Indians. Marquette and Jolliet, with five other men, left the mission of St. Ignace at Michilimackinac in two bark canoes on May 17. To reach the Mississippi River, they travelled across Lake Michigan into Green Bay, up the Fox River and down the Wisconsin River. Descending the Mississippi, in June, they met the Peoria and Moingwena bands of Illinois at the Haas/Hagerman Site near the mouth of the Des Moines River in Clark County, northeastern Missouri. They met another Illinois band, the Michigamea, when they reached present-day Arkansas.