The Ohio River was there long before the US. If you mean when did the US take control of the area then it was in 1783 after the Revolutionary War.
The Ohio River.
The river is IN the U.S. It is the southern border of Ohio and is later connected to the Mississippi River. = D
the ohio river
Ohio River
The US river and state name is Ohio.
1812
The Mississippi River, being fed by the Ohio River and Colorado River.
The Ohio River
Ohio River Actually, the Ohio River flows to the Southwest... rather than "due" West...
Ohio is the closest state to the Ohio River that's why it is called the Ohio River.
MARCH 1 1803
The Ohio River