The Teesta River (Pron:ti:ˈstə) or Tista (, Hindi टीस्ता, Bengali তিস্তা) 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 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 . It drains an area of .