The Chandragiri River, also known as the Payaswini River in Karnataka and as the Perumpuzha River in Kerala, is the longest river in Kasaragod district, Kerala, India. The river is a historical treasure of Chemnad. It was named after the Mauryan emperor Chandragupta Maurya.

The river originates in the Talakaveri Wildlife Sanctuary in the Western Ghats of Kodagu district, Karnataka. It flows through towns including Sullia, Jalsoor, Parappa, Adoor, Chengala, Kasaragod and Chemnad and then later flows into the Arabian Sea. In Sullia taluk, it is the major water source for domestic and agricultural purposes. Chemnad is considered as the Land Of Chandragiri.

The Chandragiri or Perumpuzha River is considered the traditional boundary between the Tulu Nadu and Malayalam regions of Kerala.

In 16th-century Portuguese geographies, the Chandragiri River is called the "Rio Cangerecora", and identified as the boundary between the "province of Canará" (Kannada-speaking coastal south Karnataka, vassal of "Bisnaga", Vijayanagara Empire) and the independent kingdoms of "Malabar" (Kerala).

The 17th-century Chandragiri Fort is located on the river.

The Chandragiri River originates from the northern slopes of the Greater Talacauvery National Park in the Western Ghats at the Kodagu district, Karnataka. Initially the river flows through the Malenadu region of Karnataka passing the Pushpagiri Wildlife Sanctuary and flowing through several hilly towns in Kodagu and Dakshina Kannada like Adyadka, Biliyar, Parivarkana, Paladka, Sullia, Pilikodi and Kanyana. Chandragiri then enters Kerala and flows through several hilly towns in the eastern part of the Kasaragod district – Panjikkal, Kottyadi, Adhur, Poovadka, Kottamkuzhy, Bethurpuzha, Kundamkuzhy, Kolathur, Muliyar and Bovikanam. At Bovikanam its major tributary, Kudumbur River merges with Perumpuzha. Then the river enters into the Malabar plains where it flows through Thekkil, Chengala, Chattanchal, Perumbala, Chemnad and Kasaragod. The Chandragiri River empties into the Arabian Sea at Thalangara in Kasaragod town.

The River Chandragiri's largest tributary is the Kudumbur River, which joins the Payaswini on its left bank east of Chattanchal.

• Kanhangad
• Kasaragod
• Mangalore