Cagayan River is known to be the longest river in the Philippines.
A. Cagayan River is also known as Rio Grande de Cagayan.
B. It is located in the Cagayan Valley region in northeastern part of Luzon Island.
C. The river's headwaters are at the Caraballo Mountains of the Central Luzon.
D. It has a total length of approximately 505 kilometers (314 miles).