The Illinois River is a major waterway in the state of Illinois, flowing approximately 273 miles from its source at the confluence of the Des Plaines River and the Kankakee River to its mouth at the Mississippi River. It serves as an important transportation route and is vital for local ecosystems, supporting a diverse range of wildlife. Historically significant, the Illinois River played a crucial role in the development of the region, facilitating trade and settlement. Today, it is a popular destination for recreational activities such as fishing, boating, and birdwatching, attracting visitors from across the country.