The Tumen river is located in Northeast Asia and acts as a border between China and the Democratic People's Republic of Korea (DPRK) in its upper reaches, and between DPRK and the Russian Federation near the mouth.

The Tumen river originates in the Changbai Mountain Range which is the sacred mountain of Korean culture and flows into Peter the Great Bay (Sea of Japan). The length of Tumen river mainstream extends 546 km, with average annual runoff of 6.76 billion cubic meters.

The Tumen river's drainage area covers China's Yanbian Korean Autonomous Prefeture (about 70%) and DPRK's North Hamgyong Province (nearly 30%). The Russian portion of the watershed (less than 1%) includes a small area of the Khasan wetlands in Primosky Territory. The total population in the drainage area is around 2.2 million, with 1,710,000 (more than 75%) living in China's portion and around 500,000 in DPRK's portion.

The Tumen Region is host to a range of unique but threatened environmental resources that are of regional and global significance. They include the Tumen River and its tributary system itself, as well as coastal wetlands and offshore areas like the Peter the Great Bay. The area's fragile ecosystems include steppe and temperate forests that are habitats of the Siberian Tiger, the Amur Leopard and several species of cranes, to name just a few.