The river rises in the western portion of Arunachal Pradesh, India, and flows southwest first into the Bhutanese district (or dzongkhag) of Trashiyangtse and then into Tashigang.
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Continuing to the southwest, the river forms the boundary between Tashigang and Mongar, and then between Pemagatsel and Mongar.
Sherubtse College is located near the small town of Kanglung in the dzongkhag of Tashigang in eastern Bhutan.