Cagayan Valley (Lambak ng Cagayan in Filipino) is a region of the Philippines, also designated as Region II or Region 02. It is composed of five provinces, namely: Batanes, Cagayan, Isabela, Nueva Vizcaya, and Quirino. Its regional center is Tuguegarao City.
Most of 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, in the town of Aparri, Cagayan. The Babuyan and Batanes island groups that lie in the Luzon Strait also belong to the region.
The Philippine Republic's Region II, Cagayan Valley, contains two landlocked provinces, Quirino and Nueva Vizcaya. Both are relatively small in size (3057 sq.km. for Quirino, 4081 sq.km. for Nueva Vizcaya) and population (147,000 and 365,000, respectively, by the 2000 census). Both are ruggedly mountainous and heavily forested. Nueva Vizcaya is the remnant of the southern province created when Cagayan Province was divided in two in 1839. Both are ethnically and linguistically diverse, with a substrate of Agtas, Negritos who are food-gatherers with no fixed abode, overlaid by Ilonggos and others in a number of tribes, some of whom were fierce head-hunters until recently (we are firmly assured that they have given up the practice), with the latest but largest element of the population being Ilocanos. Nueva Vizcaya comprises fifteen towns; Bayombong is the capital. Agriculture in both has until recently consisted of slash-and-burn cultivation of corn and maize, though more stable cultivation of vegetables and fruits is becoming established. Both also produce logs, and are trying to manage their forest resources so that production can be sustained indefinitely. They have deposits of gold, silver, copper, iron. Nueva Vizcaya has sand and clay. At Balete Pass in Nueva Vizcaya the retreating Japanese under General Yamashita dug in and held on for three months against the American and Filipino forces who eventually drove them out; the pass is now called Dalton Pass in honor of General Dalton, USA, who was killed in the fighting.