The Nyang has a length of 307.5 km and originates at 5,000 meters above the sea level from the Cuomuliangla, west of the Mila Mountain. The river joins the Yarlung Tsangpo in Cemeng, Nyingchi, 2,580 meters below its source. With an average flow of 538 cubic meters per minute, it has an aquatic power potential of 2.08 million kilowatts. Its largest tributary is the Ba River.
According to a Chinese government website aimed at investors, the Niyang River valley has an area of 24,800 km², including 175,700 mǔ (117 km²) of cultivated land, 209,800 mǔ (140 km²) of usable wasteland, 24.75 million mǔ (16,500 km²) of forestry land, and 12 million mǔ (8,000 km²) of usable grassland. It is also reported to contain 1,500 kinds of wild animals and plants, 310,000,000 million m³ of wood reserves and 18 million kw of hydroenergy resources.