The Grand Village of the Illinois, also called Old Kaskaskia Village, is a site significant for being the best documented historic Native American village in the Illinois River valley. It was a large agricultural and trading village of Native Americans of the Illinois confederacy, located on the north bank of the Illinois River near the present town of Utica, Illinois. French explorers Louis Joliet and Father Jacques Marquette came across it in 1673. The Kaskaskia, a tribe of the Illiniwek people lived in the village. It grew rapidly after a French mission and fur trading post were established there in 1675, to a population of about 6,000 people in about 460 houses. Around 1691 the Kaskaskia and other Illiniwek moved further south, abandoning the site due to pressure from an Iroquois invasion from the northeast.

The Illinois River is a principal tributary of the Mississippi River at approximately 273 miles (439 km) in length. Located in the U.S. state of Illinois, the river has a drainage basin of 28,756.6 square miles (74,479 km2). The Illinois River begins with the confluence of the Des Plaines and Kankakee rivers in the Chicago metropolitan area, and it generally flows to the southwest across Illinois, until it empties into the Mississippi near Grafton, Illinois. Its drainage basin extends into southeastern Wisconsin, northwestern Indiana, and a very small area of southwestern Michigan in addition to central Illinois. Along its shores are several river ports, including Peoria, Illinois. Historic and recreation areas on the river include Starved Rock, and the internationally important wetlands of the Emiquon Complex and Dixon Waterfowl Refuge.