The Illinois River is a major tributary of the Mississippi River and an integral part of the Chicago Waterway system. It connects with the 1200-mile commercially navigable river network in the upper Midwest. It supports the 122 million tons of cargo shipped on barges along the Mississippi River to their destinations. http://www.umrba.org
The confluence of the Des Plaines, Du Page and Kankakee Rivers created the much larger Illinois River, which is 332 miles long. The Illinois River Valley collects 8.2 million tons of sediment from numerous streams. In addition to the rivers mentioned, other tributaries include the Fox, Vermilion, Mackinaw, Sangamon, Spoon and La Moine Rivers. The banks of the Illinois River are marked with lakes and rough, backwoods country. The mouth of the Illinois River is located in southwestern Illinois at Grafton in Jersey County on the Mississippi River. http://www.enjoygrafton.com
Native Americans learned this ancient trade route and used it regularly. When Pere Marquette and Louis Jolliet reached a state of exhaustion from rowing upstream on the Mississippi River, local tribes taught them the easier route up the Illinois River to Lake Michigan.
Today, navigation along the Illinois River proceeds by a series of locks and dams to the Mississippi River. Commodities are then sent to their destinations along ‘the mighty Mississippi ’, including New Orleans at the Gulf of Mexico. Transporting goods on barges via Illinois waterways is popular with farmers and ranchers because it’s considerably less expensive than shipping by truck and railroad. For the same reason, it is also popular with manufacturing and other industries.
Water quality is an important consideration for citizens and local and state governments, especially because major Illinois waterways are used non-stop for trade. The water quality of the Illinois River is rated ‘fair,’ indicating it’s adequate for navigation and recreational uses.