In the north, the Hengduan Mountain

In the north, the Hengduan Mountains form the border with China. Hkakabo Razi, located in Kachin State, at an elevation of 5,881 metres (19,295 ft), is the highest point in Burma.[279] Many mountain ranges, such as the Rakhine Yoma, the Bago Yoma, the Shan Hills and the Tenasserim Hills exist within Burma, all of which run north-to-south from the Himalayas.[280] The mountain chains divide Burma's three river systems, which are the Irrawaddy, Salween (Thanlwin), and the Sittaung rivers.[281] The Irrawaddy River, Burma's longest river, nearly 2,170 kilometres (1,348 mi) long, flows into the Gulf of Martaban. Fertile plains exist in the valleys between the mountain chains.[280] The majority of Burma's population lives in the Irrawaddy valley, which is situated between the Rakhine Yoma and the Shan Plateau.