Cagayan Valley, officially designated as Region II, is an administrative region in the Philippines occupying the northeastern section of Luzon. It covers 5 provinces, namely, Batanes, Cagayan, Isabela, Nueva Vizcaya, and Quirino. The regional center is the City of Tuguegarao.

Its population as determined by the 2020 Census was 3,685,744. This represented 5.93% of the overall population of the Luzon island group, or 3.38% of the entire population of the Philippines. Based on these figures, the population density is computed at 124 inhabitants per square kilometer or 320 inhabitants per square mile.