Tumen River Basin
Tumen River forms the northeastern frontier of North Korea with China and Russia. The Tumen originates on Mount Paektu, the highest peak of the Changbai Mountains along the China-Korea border. It then flows with its short tributaries through narrow gorges east-northeast to HoeryÅng, north to OnsÅng, and southeast to the Sea of Japan (East Sea). It is the third longest river in Korea, with a length of 521 km; but its drainage basin is only 10,513 square km, and the plain area is formed only downstream, in the southeast.