The Ohio River.
It's along the southern border, between Ohio and West Virginia/Kentucky. The southern edge of the state is defined by the river.
West Virginia, Ohio, Illinois, and Indiana form the northern border of Kentucky, along the Ohio River.
Ohio River
Cincinnati borders the state of Kentucky to the south and Indiana to the west. The Ohio River forms the southern boundary between Cincinnati and Kentucky.
Illinois is bordered by the Ohio River to the south.
The Ohio River formed the southern border of the Northwest Territory.
none of the rivers form the southern border of Indiana, but the Ohio river forms the southern border of Ohio.
The southern border of Ohio is 981 miles and is defined by the Ohio River. It is also the southern border of Indiana and Illinois.
The Ohio River and Ohio River Valley boarder the southern part of Ohio.
Ohio River
The border is the Ohio River.