Tista River an important river of the northern region of Bangladesh. According to Hindu mythology, it originated from the breast of Devi Parvati (Goddess Parvati). Actually it originates in Chitamu Lake in the Sikkim Himalayas at an altitude of about 7,200 m and comes down first to the Darjeeling plain and then to the Duar plain of West Bengal (India). It flows through a magnificent gorge known as Sivok Gola in Darjeeling. It is a wild river in the Darjeeling Hills where its valley is clothed with dense forest, but its drainage area in the mountains is only 12,500 sq km. It enters Bangladesh at the Kharibari border of Nilphamari district.
Up to the close of the 18th century it flowed directly into the ganges. The excessive rains of 1787 created a vast flood and choked the original atrai channel. This resulted in the Tista bursting into the ghaghat which at that time was a very small river. After passing through Lalmonirhat, Rangpur, Kurigram and Gaibandha districts this deluge falls into the jamuna south of Chilmari riverport. The total length of the river is about 315 km, of which nearly 115 km lies within Bangladesh. The land movement, earthquakes, floods and geological structural changes in the northern part of Bangladesh affected the original flows of the karatoya, Atrai and Jamuneshwari rivers. The present Tista is the result of these changes and the accumulated flows of the Karotoya, Atrai and Jamuneshwari rivers. Actually the Bangla name Tista comes from Tri-Srota or three flows. Tista has a mean monthly discharge of about 2,430 cumec. A number of old channels that were occupied by this river and the Karatoya through which it joined the Ganges are still known as the Buri Tista or Old Tista. [Mesbah-us-Saleheen]
See map in brahmaputra-jamuna river system.