Teesta River - On the way to Gangtok, Sikkim, India
River Teesta or Tista ( Nepali: टिष्टा Hindi टीस्ता ) is said to be the lifeline of the Indian state of Sikkim, flowing for almost the entire length of the state and carving out verdant Himalayan temperate and tropical river valleys. The emerald-coloured river then forms the border between Sikkim and West Bengal before joining the Brahmaputra as a tributary in Bangladesh. The total length of the river is 309 km (192 mi), draining an area of 12,540 km².
The river originates from Tso Lhamo in North Sikkim at an elevation of 5,330 m (17,487 ft) above sea level in the Himalaya. This lake lies to the east of the Donkia pass next to the Western base of Pauhunri and is formed by the melting of the Tista Khantse glacier.
The Teesta River is then fed by rivulets which arise in the Thangu, Yumthang and Donkia-La ranges. The river then flows past the town of Rangpo where Rangpo River merges into it and where it forms the border between Sikkim and West Bengal up to Teesta Bazaar. Just before the Teesta Bridge, where the roads from Kalimpong and Darjeeling join, the river is met by its main tributary, the Rangeet River. At this point, it changes course southwards flowing into West Bengal. The river hits the plains at Sevoke, 22 km (14 mi) north of Siliguri, where it is spanned by the Coronation Bridge which links the northeast states to the rest of India. The river then courses its way to Jalpaiguri and then to Rangpur district of Bangladesh, before finally merging with the mighty Brahmaputra at Fulchori.