The Manas River, known in Bhutan as the Drangme Chhu, is a transboundary river in the Himalayan foothills between southern Bhutan, India, and China. It is the largest of Bhutan's four major river systems, with the other three being the Amo Chu or Torsa River, the Wang Chu or Raidak, and the Puna Tshang Chu or Sankosh. It is met by three other major streams before it again debouches into India in western Assam. The river flows for a total length of 400 kilometres (250 mi), including through Tibet for 24 km (15 mi), Bhutan for 272 kilometres (169 mi), and Assam for 104 kilometres (65 mi) before it joins the mighty Brahmaputra River at Jogighopa. A major tributary of the Manas, the Aie River, joins it in Assam at Bangpari.