The southern border of Indiana is the OHIO River (which separates it from Kentucky.)
The Potomac river
The Ohio River
The Narbada River
It is the Danube River.
The southern half of the eastern boundary of Alabama is the Chattahoochee River.
Rio Grande river
The Potomac River divides Maryland and Virginia (The Southern Border) , but Virginia does not own half of the Potomac River.
Rio Grande River
Mississippi river
The Ohio River forms Ohio's southern border.
The Ohio river is located on the southern boundary of Indiana and Ohio. The Ohio River also borders northern Kentucky.