Which river forms the northern border of West Virginia?

The Ohio River forms the northern border of West Virginia, defining a critical geographic and historical boundary for the state. This river serves as a significant waterway that has played a vital role in commerce and transportation throughout the region.

The Ohio River flows from its origin in Pennsylvania, traveling westward, and ultimately emptying into the Mississippi River, which has been pivotal for trade and settlement in the United States. Its borders with neighboring states, such as Ohio and Kentucky, have influenced the economic and cultural development of West Virginia.

In contrast, while the other rivers mentioned have their own significance, they do not serve as the northern boundary. The Cumberland River is located to the south of West Virginia, the Tennessee River is even further south, and the Potomac River runs along the eastern border, not the northern border of the state. This differentiates the Ohio River as the correct answer.