Illinois
Illinois is a mapped river in the YearMaps hydrographic index. River courses organise settlement, agriculture and frontier-making more durably than any political boundary, and this reach is indexed against the dams, lakes and cities within its catchment.
- Feature Class
- River
- Coordinates
- 40.57°, -89.68°
About Illinois
The Illinois River (Miami-Illinois: Inoka Siipiiwi) 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 banks are several river ports, including the largest, 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.
The river was important among Native Americans and French traders as the principal water route connecting the Great Lakes with the Mississippi. The French colonial settlements along these rivers formed the heart of the area known as the Illinois Country in the 17th and 18th centuries.
Encyclopedic summary adapted from Wikipedia: Illinois River (CC BY-SA 4.0).
Illinois in Depth
History
The Illinois River valley has long been an important transportation route for civilizations. The portages between the Des Plaines and Chicago Rivers and the Kankakee and St. Joseph rivers allowed Native Americans, Europeans, and later Americans access between the Great Lakes and the Mississippi basin. The first European presence in the area was the Jesuit mission founded in 1675 by Father Jacques Marquette on the banks of the Illinois across from Starved Rock at the Grand Village of the Illinois, near present-day Utica. The Illinois Confederation were the primary inhabitants of the valley.
Geology
South of Hennepin, the Illinois River follows the ancient channel of the Mississippi River. The Illinoian Stage, about 300,000 to 132,000 years ago, blocked the Mississippi near Rock Island, diverting it into its present channel. After the glacier melted, the Illinois River flowed into the ancient channel. The Hennepin Canal roughly follows the ancient channel of the Mississippi upstream of Rock Island.
The modern channel of the Illinois River was shaped in a matter of days by the Kankakee Torrent. During the melting of the Wisconsin Glacier about 18,500 years ago, a lake formed in present-day Indiana, comparable to one of the modern Great Lakes. The lake formed behind the terminal moraine of a substage of that glacier.
Sections adapted from Wikipedia: Illinois River (CC BY-SA 4.0).
Major River Dossiers
Hand-written studies of the great river systems of history.
Connected Reaches
Nearby watercourses in the same drainage network.
Water Bodies in the Catchment
Settlements Along the Reach
Hydraulic Infrastructure Nearby
Surrounding Terrain
Illinois: Quick Answers
- Where is Illinois?
- Illinois is located in United States, at 40.5747° N, 89.6793° W.
- Are there dams on the Illinois?
- No dam on the Illinois is recorded in the YearMaps dam index, which covers major structures only.