W. Va. Code § 51-3-3: Jurisdiction over watercourses.

When any river or watercourse lies between any counties in this state, the circuit and county courts and justices for the counties on each side, respectively, shall have concurrent jurisdiction over so much thereof as is opposite said counties. And the circuit and county courts and justices for counties lying on the waters bounding the state shall have jurisdiction respectively over such waters opposite said counties, so far as the jurisdiction of this state extends.