Santiago, officially the City of Santiago, is an independent component city in the Cagayan Valley region of the Philippines. According to the 202…Santiago, officially the City of Santiago, is an independent component city in the Cagayan Valley region of the Philippines. According to the 2020 census, it has a population of 148,580 people. It is formerly known as Carig during the time of the Spanish, it is located between the southwestern part of Isabela and the northwestern boundary of Quirino in northeastern Luzon island of the Philippines. It is the gateway to the vast plains of Cagayan Valley.