Valley is the large mass of land in the northeastern region of Luzon, comprising the provinces of Cagayan, Isabela, Nueva Vizcaya, Quirino, and the Batanes group of islands. It is bordered to the west by the Cordillera mountain range, to the east by the Sierra Madre, to the south by the Caraballo Mountains, and to the north by the Luzon Strait. The region contains two landlocked provinces, Quirino and Nueva Vizcaya, which 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. They are ethnically and linguistically diverse, with a substrate of Agtas, Negritos who are food-gatherers with no fixed abodes, overlaid by Ilongots and others in a number of tribes, some of whom were fierce head-hunters (they have given up the practice), with the latest but largest element of the population being the Ilocanos, closely followed by the Ibanags. Administrative divisions Cagayan Valley comprises five provinces, one independent city, three component cities, 89 municipalities, and 2,311 barangays. Provinces Governors and vice governors Cities and Municipalities Demographics Economy The province of Isabela and the city of Santiago are notably the most progressive province and richest city in the region, respectively. Isabela was the 9th richest province in the Philippines in 2021, being the only province from the region to be included in the list. The city of Tuguegarao is the center of excellence in education, commerce, trade and culture and as the economic center of the region, the city continuously aims for outstanding performance and competence in administration, citizen participation, community and economic development, cultural arts, education, fiscal management, infrastructure, intergovernmental cooperation, planning, public safety, recreation and leisure services, social services, and technology. Its economy gradually shifted from agriculture to secondary/tertiary economic activities such as trading, commerce and services. The shift was ushered by city's role as the Regional Government Center and Center of Commerce in Northern Luzon. Tuguegarao City was included to be one of the digital cities for 2025 to sustain the rapid growth of the Information Technology and Business Process Management and to promote development in the city. The program (Digital Cities 2025) was created through a partnership between the DICT, the IT and Business Process Association of the Philippines (IBPAP), and Leechiu Property Consultants (LPC). Cauayan is a component city in the province of Isabela. It is dubbed as the Ideal