It originates from the Bitang Lake at Kupup, Gangtok District, Sikkim, near the Jelep La pass below Dongkya Mountain Range.

Further it passes through Neora Valley National Park, Chapramari Wildlife Sanctuary and Gorumara National Park in West Bengal along with cities and towns, like Paren, Gairibas, Jhalong, Dhupguri, Falakata, Mathabhanga and flows through Kalimpong, Jalpaiguri and Cooch Behar districts in West Bengal, India before entering Bangladesh at Mogolhat, Lalmonirhat District of Rangpur Division.

The combined stream meet at Bindu to increase the volume of Jaldhaka River, thus forming a riverine boundary with India and Bhutan in the left bank.

The river flows through the three North Bengal districts of Kalimpong, Jalpaiguri and Cooch Bihar.

The upper course is famous for crops like ginger, medicinal herbs and fruits like oranges and pomegranate.