The Dangqu (Chinese: 当曲, p Dāngqū) or Dam Chu (Tibetan: འདམ་ཆུ, w 'Dam Chu, lit. "Marshy River") is a 234 km (145 mi) river in Qinghai province in the People's Republic of China. It is the geographic headwater of the Yangtze River, although the nearby Ulan Moron is traditionally regarded as the source.^[1]

The Dangqu runs from its source in the Tanggula Mountains (唐古拉山) to its confluence with the Ulan Moron, where the Tongtian River is formed.