Tso Lhamo lake in the North Sikkim Himalayas, located 4 kilometres south of the India-Tibet international border, is the source of the 315-kilometer Teesta river. Teesta Khangse glacier (also known as Pahunri glacier) is thought to be the source of Teesta. It is located at an altitude of 7,068 metres on the India-Tibet border.
Teesta then flows through gorges and rapids in the higher reaches of Sikkim until it reaches the Darjeeling hills, covering 172 kilometres, before widening and meandering through the plains of West Bengal for about 98 kilometres before entering Bangladesh and flowing into the Brahmaputra at Fulchori.
• The Teesta River is a tributary of the Brahmaputra River, which flows through India and Bangladesh and is known as the Jamuna in Bangladesh.
• It begins near Chunthang, Sikkim, in the Himalayas and flows south through West Bengal before entering Bangladesh.
• Originally, the river flowed southward, emptying directly into the Padma River (the Ganga's main channel in Bangladesh), but around 1787, it changed its course to flow eastward, joining the Jamuna.
• It is fed by rivulets that originate in the mountain ranges of Thangu, Yumthang, and Donkha. The river then flows past Rangpo, where it joins the Rangpo River and forms the border between Sikkim and West Bengal, until it reaches Teesta Bazaar.
• The river meets its main tributary, the Rangeet, just before the Teesta Bridge, where the roads from Kalimpong and Darjeeling meet.
• The Teesta Bazaar is a small town on the right bank of the river, near the intersection of the Siliguri-Gangtok National Highway. Beautifully handcrafted local items such as thankas (religious hand paintings on scrolls), lanterns, silver jewellery, crockery, and local food items are popular in this market area.
• The Teesta flows with a very strong current between Rangpo town and the railway bridge (popularly known as Lohapul or iron bridge) on it as it enters the plains at Sevoke, making it ideal for white river rafting. Group rafting is available in towns like Teesta Bazaar and Melli.