Black

"The Black River is a 125-mile-long (201 km) blackwater river that empties into the eastern end of Lake Ontario on the shore of Jefferson County, New York in the United States. The origin of the name is not clear, but it may stem from the natural tannic acid that darkens the water in places. The river flows in a generally northwest direction, with its valley dividing the Adirondack Mountains on the east from the Tug Hill region to the west."