There are three: the Mississippi, the Ohio, and the Wabash.
The Colorado River.
The Columbia River
The Mississippi River forms the western border of Illinois.
Mississippi.
Mississippi river
Illinois has the longest common border with Missouri.
Illinois is bordered by Wisconsin to the north.
Illinois.
Ohio
The distance from Chicago to the Illinois border varies depending on the specific location of the border. On average, it is approximately 30-40 miles from downtown Chicago to the Illinois state border.
The US State of Illinois and the US State of Kentucky share a border with the Ohio River that runs between the two States. There is no land border with each other.
The Illinois River is entirely contained within the State of Illinois.