It originates in the Tokpo Shiri Glacier, about 7–10 kilometres east of Nyamjang Chu, and flows down to the river.

The Sumdorong Chu valley was the site of a standoff between India and China in 1986–1987 which, despite giving rise to the fears of another war, deescalated successfully.

Subsequently, India and China formulated agreements for managing future border tensions.

[3][4] Sumdorong Chu flows in a disputed border region between Tibet's Tsona County and Arunachal Pradesh's Tawang district.

It was initiated by China moving a company of troops to Wangdung, a pasture to the south of Sumdorong Chu which India held to be part of its territory.