The Online Encyclopedia and Dictionary






Illinois River

This article is about the river in the U.S. state of Illinois. For other rivers with this name see Illinois River (disambiguation)

The Illinois River is a principal tributary of the Mississippi River, approximately 273 miles (439 km) long, in the state of Illinois in the United States. The river drains a large section of central Illinois, with a drainage basin of 40,000 square miles (104,000 kmē). The river was important among Native Americans and early French traders as the principal water route connecting the Great Lakes with the Mississippi. The colonial settlements along the river formed the heart of the area known as the Illinois Country. After the construction of a canal in the 19th century, the river's role as link between Lake Michigan and the Mississippi was extended into the era of modern industrial shipping.



It is formed by the confluence of the Kankakee and Des Plaines rivers in western Grundy County, approximately 10 mi (16 km) southwest of Joliet. It flows west across northern Illinois, passing Morris and Ottawa, where it is joined by the Fox River. At La Salle it is joined by the Vermillion River , then flows west past Peru, and Spring Valley. In southeastern Bureau County it turns south, flowing southwest across western Illinois, past Lacon and downtown Peoria, the chief city on the river.

South of Peoria it is joined by the Mackinaw River and then passes through the Chautauqua National Wildlife Refuge . Opposite Havana it is joined by the Spoon River. Opposite Browning it is joined by the Sangamon River. It is joined by the La Moine River approximately 5 mi (8 km) southwest of Beardstown.

South of its confluence with the La Moine, it turns south, flowing roughly parallel with the Mississippi across southwestern Illinois. It is joined by the Macoupin Creek on the border between Greene and Jersey counties, approximately 15 mi (24 km) upstream from its confluence with the Mississippi.

For the last 20 mi (32 km) of its course, it is separated from the Mississippi by only 5 mi (8 km). It joins the Mississippi near Grafton, approximately 25 mi (40 km) northwest of downtown St. Louis and approximately 20 mi (32 km) upstream from the confluence of the Missouri and the Mississippi.


The Illinois River valley was one of the strongholds of the Illiniwek confederation of Native Americans. The French first met the natives here in 1673. The first European settlement in the state of Illinois was the Jesuit mission founded in 1675 by Father Jacques Marquette on the banks of the Illinois at Starved Rock. In 1680, Robert Cavelier de La Salle built the first fort in Illinois along the river at the present site of Peoria where the Jesuits later relocated.

Modern use

From 1905 to 1915, more freshwater fish were harvested from the Illinois than from any other river in the United States except for the Columbia River. The river was once a major source of mussels for the shell button industry. Overfishing, habitat loss and pollution have eliminated most commercial fishing except for a small mussel harvest to provide shells to seed pearl oysters overseas. The river is still an important sports fishing resource.

The Illinois forms part of a modern waterway that connects the Great Lakes at Chicago to the Mississippi River. The waterway was originally established by the building of the Illinois and Michigan Canal which connected the Illinois River to the Chicago River. When the Chicago River was later reversed, the pollution and sewage of the city of Chicago flowed down into the Illinois River. The Illinois and Michigan Canal has since been replaced by the Illinois Waterway including the Chicago Sanitary and Ship Canal. The river is controlled by five lock and dams to facilitate river traffic. The waterway is heavily trafficked by barges transporting bulk goods such as grain and oil.

See also

Last updated: 05-07-2005 10:45:47
Last updated: 05-13-2005 07:56:04