Calabarzon (/kɑːlɑːbɑːrˈzɒn/), formally known as the Southern Tagalog Mainland,[3] is an administrative region in the Philippines, designated as Region IV-A. The region comprises five provinces: Batangas, Cavite, Laguna, Quezon, and Rizal; and one highly urbanized city, Lucena. The region is the most populous region in the Philippines according to the Philippine Statistics Authority, having over 14.4 million[4] inhabitants in 2020, and is also the country's second most densely populated after the National Capital Region. [1]