Chandragiri River originates from the Pattimala Hills in Kodagu District of Karnataka. It is the longest river which flows through Kasargod District of Kerala. Payaswani is the main tributary of this river. The river has a length of 105 km and a basin area of 1406 sq km. Chandragiri River drains a catchment area of 1406 sq km out of which 836 sq km lie in Karnataka and the remaining in Kerala. The river flows towards the west and links with Machipuram. After that it merges in the Arabian Sea.
The river got its name Chandragiri from the place of its orgin, Chandragupta Vasti, where the Maurya emperor Chandragupta is believed to have spent his last days as a sage. Chandragiri, a famous tourist destination in Kasargod District, located on the banks of the river is a major point of attraction.