San Juan, officially the City of San Juan, is a highly urbanized city in the National Capital Region of the Philippines. According to the 2020 cen…San Juan, officially the City of San Juan, is a highly urbanized city in the National Capital Region of the Philippines. According to the 2020 census, it has a population of 126,347 people. It is geographically located at Metro Manila's approximate center and is also the country's smallest city in terms of land area.