What separates Cincinnati from Kentucky?

Answer 1

Cincinnati is on the northern shore of the Ohio River. Kentucky is south of the Ohio River, so in gneeral terms the Ohio River separates Cincinnati, and all of Ohio, from Kentucky.

More specifically, however, the Ohio River is within the boundary of Kentucky. In most cases, where two states are separated by a river, the border is set in the middle of the river. In the case of the Ohio River, The Commonwealth of Kentucky extends to the northern low water mark of 1793 (Supreme Court Ruling)-or about 80% across the river, so the river belongs mostly to Kentucky.

The U.S. Supreme court ruling that established the line was done for several reasons, mostly because Kentucky objected to an Indiana nuclear power plant that would discharge into the Ohio River. But also because if the high water mark were to be used, half of downtown Cincinnati would fall under the jurisdiction of Kentucky thanks to the 1937 flood which reached 80 feet, 55 feet above current average height, or 28 feet above current flood stage.

As recently as 1997 (7 years after the Supreme Court ruling that set the boundary line at the 1793 low-water mark) the local running joke during the 1997 flood was that the whole Cincinnati Riverfront Stadium problem and the proposed structure that would become Great American Ballpark and Paul Brown Stadium were Kentucky's problem now.