The Japanese government categorizes it as a Class 1 river. With a length of , the Naka drains an area of , including parts of neighboring Fukushima Prefecture. Its source is at Nasu-dake in Nikkō National Park.
The Japanese government categorizes the Naka River as a Class 1 river, with a length of and draining an area of , including parts of neighboring Fukushima Prefecture. Its source is at Nasu-dake in Nikkō National Park.