- Gandak River originates in the Great Himalayan Range on the Tibet-Nepal border.
- From this junction to the Indian border the river is called the Narayani.
- It flows in central Nepal and northern India.
- It is a north-bank tributary of the Ganga in India.
- Kali Gandak, Mayangadi, Bari and Trishuli are the major tributaries of the river.
- Its drainage area is 46,300 sq km out of which 7620 sq km is in India.