Ohio River
The Ohio River forms the southern borders of Ohio and Indiana.
The Ohio River forms Ohio's southern border.
The Mississippi river forms the boundary between Missouri and Illinois!
The Ohio River forms the borders of West Virginia, Ohio, Kentucky, Indiana, and Illinois. The border terminates at the confluence with the Mississippi and the border with Pennsylvania.
The Mississippi River forms the border between Missouri and Illinois.
Illinois is bordered by Wisconsin to the north, Michigan via a water boundary in Lake Michigan to north east; Indiana to the east; Kentucky to south east, the Mississippi River forms a natural border with Missouri and Iowa to the west.
Indiana
Lake Michigan forms the northeastern border of the State of Illinois.
Indiana and Illinois
Wisconsin!Wisconsin does NOT share a river border with Illinois, BUT Iowa, Kentucky, and Missouri do.
Indiana is bordered by six states: to the north is Michigan, to the east is Ohio, to the south is Kentucky, and to the west are Illinois and a small portion of Missouri. Additionally, the Ohio River forms part of Indiana's southern border with Kentucky. These neighboring states contribute to Indiana's diverse cultural and geographic influences.