伊利诺伊河（英语：Illinois River）是密西西比河的一条主要支流,，长约273英里（439公里），位于伊利诺伊州，其流域面积为28,070平方英里（72,701平方公里），覆盖了伊利诺伊州中部，并延伸至威斯康辛州和印第安纳州境内。对于美国原住民和早期法国商人而言，这条河是重要的连接五大湖地区和密西西比河的水道。The French colonial settlements along the river formed the heart of the area known as the Illinois Country. After the construction of the Illinois and Michigan Canal and the Hennepin Canal in the 19th century, the role of the river as link between Lake Michigan and the Mississippi was extended into the era of modern industrial shipping.

The Illinois River is a principal tributary of the Mississippi River, approximately 273 miles (439 km) long, in the State of Illinois. The river drains a large section of central Illinois, with a drainage basin of 28,756.6 square miles (74,479 km). The drainage basin extends into Wisconsin and Indiana. This river was important among Native Americans and early French traders as the principal water route connecting the Great Lakes with the Mississippi. The French colonial settlements along the river formed the heart of the area known as the Illinois Country. After the construction of the Illinois and Michigan Canal and the Hennepin Canal in the 19th century, the role of the river as link between Lake Michigan and the Mississippi was extended into the era of modern industrial shipping.