Ohio is bounded by the Ohio River, but nearly all of the river belongs to Kentucky and West Virginia. In 1980, the U.S. Supreme Court held that, based on the wording of the cessation of territory by Virginia (which at the time included what is now Kentucky and West Virginia), the boundary between Ohio and Kentucky (and, by implication, West Virginia) is the northern low-water mark of the river as it existed in 1792. Ohio has only that portion of the river between the river's 1792 low-water mark and the present high-water mark. The border with Michigan has also changed, as a result of the Toledo War, to angle slightly northeast to the north shore of the mouth of the Maumee River.
ohio is bounded by the ohio river but nearly all of the river belongs to kentucky and west virginia in 1980 the us supreme court held that based on the wording of the cessation of territory by virginia (which at the time included what is now kentucky and west virginia) the boundary between ohio and kentucky (and by implication west virginia) is the northern low-water mark of the river as it existed in 1792 ohio has only that portion of the river between the river's 1792 low-water mark and the present high-water mark the border with michigan has also changed as a result of the toledo war to angle slightly northeast to the north shore of the mouth of the maumee river