Drangme Chhu river drains a large portion of central and eastern Bhutan. The word Chhu means "river" or "water" in Dzongkha. 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. The south flowing Kulong and the west flowing Gamri join the Drangme near the town of Tashigang. Continuing to the southwest, the river forms the boundary between Tashigang and Mongar, and then between Pemagatsel and Mongar. Along this stretch is the confluence with another major tributary, the south flowing Kuru, and a name change to the Manas River. Shortly before turning south and leaving Bhutan, the river is augmented again with the waters of the south flowing Mangde Chhu River. The lowest point in Bhutan is at the point where the Manas Chhu river crosses into India (Assam) near the town of Manas. The river empties into the Brahmaputra River some 50 miles (80 km) south of the Bhutanese border.