Cagayan River

Cagayan River (Bannag)
Rio Grande de Cagayan
River
The river as it passes through the municipality of Jones in Isabela
Country	Philippines
Island	Luzon
Region	Cagayan Valley
Provinces	Cagayan Isabela Nueva Vizcaya Quirino
Cities and municipalities	Alcala Amulung Angadanan Aparri Cabagan Camalaniugan Cauayan Delfin Albano Dupax del Norte Dupax del Sur Echague Enrile Gamu Gattaran Iguig Ilagan Jones Lal-lo Lasam Maddela Nagtipunan Naguilian Reina Mercedes San Agustin San Pablo Santa Maria Santo Niño Santo Tomas Solana Tuguegarao Tumauini
Tributaries
- left	Chico River Magat River
- right	Ilagan River Pinacanauan River
Source
- location	Caraballo Mountains
- coordinates	16°11′08″N 121°08′39″E / 16.18556°N 121.14417°E / 16.18556; 121.14417
Mouth
- location	Babuyan Channel, Aparri
- elevation	0 m (0 ft)
- coordinates	18°20′N 121°37′E / 18.333°N 121.617°E / 18.333; 121.617Coordinates: 18°20′N 121°37′E / 18.333°N 121.617°E / 18.333; 121.617
Length	354 km (220 mi)
Basin	27,280 km2 (10,533 sq mi)
Drainage area of the river and its tributaries in northeastern Luzon

The Cagayan River, also known as the Rio Grande de Cagayan, is the longest and 2nd largest river in the Philippine Archipelago After Rio Grande de Mindanao. 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 1,524 metres (5,000 ft). The river flows north for some 354 kilometres (220 mi) to its mouth at the Babuyan Channel near the town of Aparri, Cagayan. The river drops rapidly to 91 metres (299 ft) above sea level some 227 kilometres (141 mi) 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 150 kilometres (93 mi) from Nueva Vizcaya down to its confluence with Cagayan River about 55 kilometres (34 mi) from the river mouth.