Caloocan, officially the Historic City of Caloocan (Filipino: Makasaysayang Lungsod ng Caloocan) and commonly Caloocan City (Filipino: Lungsod ng Kalookan), is the fourth most populous city in the Philippines. It is one of the 16 cities that comprise the Philippines' National Capital Region of Metropolitan Manila. It was formerly a part of the Province of Rizal of the Philippines' Southern Luzon Region. According to the 2015 census, it had a population of 1,583,978. The city's name is colloquially spelled as Kalookan. It comprises what is known as the CAMANAVA area along with cities Malabon, Navotas and Valenzuela.