The Zemu Glacier is the largest and the most famous glacier of the eastern Himalayas
. It is 26 km in length and is situated in a large U-shaped valley at the base of the Khangchendzonga massif in northwestern Sikkim
. The Teesta River rises from the snout of this glacier. Many tributary glaciers feed the trunk glacier. The side valleys, in which the glaciers lie, open into the main Zemu Valley from different directions. Icefalls and waterfalls form at the junction of the tributary glaciers.