Cagayan Valley (Lambak ng Cagayan in Filipino) is a region of the Philippines, also designated as Region II. It is composed of five provinces, namely: Batanes, Cagayan, Isabela, Nueva Vizcaya, and Quirino. Its regional capital is Tuguegarao City.
The region lies in a large valley in northeastern Luzon, between the Cordilleras and the Sierra Madre mountain ranges. Cagayan River, the country's longest river runs through its center and flows out to Luzon Strait in the north.