What river runs along the west coast of Illinois?

The Mississippi River runs along the western border of Illinois and serves as a significant geographical feature for the state, creating a natural boundary between Illinois and neighboring states such as Iowa and Missouri. This river is crucial for trade and transportation and has historically been vital for the development of regions along its banks.

The Sangamon River primarily flows through central Illinois, while the Illinois River is a tributary that flows from the north towards the south, eventually merging into the Mississippi. The Ohio River is located to the southeast of Illinois and does not border the state. Therefore, the Mississippi River is distinctly recognized as the river that lines the west coast of Illinois, emphasizing its importance both topographically and historically.