Sandberg 1889, p. 707. Sandberg, Graham (1889). "The City of Lhasa". The Eclectic Magazine of Foreign Literature, Science, and Art. Leavitt, Trow & Company. Retrieved 5 February 2015.
The origin of the river was established at 30°19′00″N90°28′00″E / 30.3166685°N 90.4666668°E / 30.3166685; 90.4666668 by the geologist Dieter Ortlam of Bremen on 14 August 1989 on a melting glacier at an altitude of 5,290 metres (17,360 ft) in the central Nyenchen Tanglha Mountains, about 15 kilometres (9.3 mi) south-west of the highest peak of 7,117 metres (23,350 ft), about 30 kilometres (19 mi) north of Yangbajain, and 15 kilometres (9.3 mi) east of the Guring La pass at 5,972 metres (19,593 ft).[5]
Another source places the origin in the Lhari County of Nagqu Prefecture.[7]
The largest tributary, the Reting Tsangpo, rises in Lhari County.