The Cagayan River is the largest river in which country?
Cagayan River Cagayan River The Cagayan River, also known as the Rio Grande de Cagayan, is the longest river in the Philippines and the largest river by discharge volume of water (followed by Rio Grande de Mindanao). It has a total length of approximately and a drainage basin covering . It is located in the Cagayan Valley region in northeastern part of Luzon Island and traverses the provinces of Nueva Vizcaya, Quirino, Isabela and Cagayan. The river's headwaters are at the Caraballo Mountains of the Central Luzon at an elevation of approximately . The river flows north for some to its mouth
Cagayan River at the Babuyan Channel near the town of Aparri, Cagayan. The river drops rapidly to above sea level some from the river mouth. Its principal tributaries are the Pinacanauan, Chico, Siffu, Mallig, Magat and Ilagan Rivers. Magat River, is the largest tributary with an estimated annual discharge of 9,808 million cubic meters. It lies in the southwestern portion of the basin, stretching approximately from Nueva Vizcaya down to its confluence with Cagayan River about from the river mouth. Both Magat and Chico Rivers have extensive drainage areas which comprise about 1/3 of the whole basin. The Ilagan River originates from