The major rivers in the Philippines are the Cagayan River, Rio Grande de Mindanao and the Agusan River. The country has a total of 421 rivers, but scientists consider 50 of them biologically dead.
The longest river in the Philippines is the Cagayan River. It is 314 miles long and is on the island of Luzon, which is in the northern section of the country. The Cagayan River is prone to flooding, specifically during heavy rains. The Cagayan River flows from the Caraballo Mountains to the Babuyan Channel. The second largest river is the Rio Grande de Mindanao, which is located in the southern portion of the Philippines on the island of Mindanao. Locals use the river to transport agricultural goods, as well as timber. The Rio Grande de Mindanao begins at the Impasug-ong mountains and ends at the Moro Gulf. In the east lies the Agusan River, which begins at the Compostela Valley and flows into the Bhutan Bay. It is the third largest river in the Philippines. Much peat and sago is found in and near this river and it is home to migratory ducks, who also live in the adjacent lakes. The Agusan is prone to flash floods during periods of heavy rain.