long secondary tributary of the Yangtze River (Chang Jiang) in central and southern China. The Yalong rises in the Bayan Har Mountains in southern Qinghai (Tsinghai) province at an elevation of nearly 16,500 feet (5,000 metres). The upper stream flows southeastward from the Bayan Har Mountains into northwestern Sichuan province. Below Ganzi it swings southward to flow along the western side of the Daxue Mountains. After making some wide loops in its course at the southern end of these mountains, the river flows into the Jinsha River near Dukou on the border of Yunnan province. The Yalong is torrential for most of its course and carries a large volume of water, and large dams and hydroelectric plants have been built along its course since the 1980s to support local economic development.

Until relatively recently, its lower course, south of the Daxue Mountains, was the limit of effective Chinese penetration to the west; its valley provided the major trade route from Chengdu in Sichuan to Dali in Yunnan and to southwestern China and northern Myanmar (Burma).