Black River

Vietnamese  Song Da,  Chinese  Li-hsien Chiang,  one of the chief tributaries of the Red River (Song Hong) in southeastern Asia. Nearly 500 miles (800 km) long, the river rises in central Yunnan province in southwestern China and flows southeastward into northwestern Vietnam on a course parallel to the Red River. Near the city of Hoa Binh, 37 miles (60 km) southwest of Hanoi, the Black River is dammed to form a reservoir that is the largest