It originates from Kupup/Bitang lake lying in Pangolakha Wildlife Sanctuary of East Sikkim in the Himalayas where it is known as the Jaldhaka River.

From there, it flows through Jalpaiguri and Cooch Behar districts of West Bengal, India, one of the seven main rivers to do so.

It then moves south and enters Bangladesh again through Phulbari Upazila of Kurigram District and continues a slow meandering course.

Three mosques, two temples, a madrassah, a primary school, and a vast tract of cultivable land with crops were devoured by the river, rendering about three thousand people homeless.

Deposition of silt has led to the formation of many small islands (chars) in the river.