San Juan (Spanish for “Saint John”) is the capital city and most populous municipality in the Commonwealth of Puerto Rico, an unincorporated territory of the United States.
As of the 2020 census, it is the 57th-most populous city under the jurisdiction of the United States, with a population of 342,259. San Juan was founded by Spanish colonists in 1521, who called it Ciudad de Puerto Rico (Spanish for “Rich Port City”).
Puerto Rico’s capital is the second oldest European-established capital city in the Americas, after Santo Domingo, in the Dominican Republic, founded in 1496, and is the oldest European-established city under United States sovereignty.
Several historical buildings are located in the historic district of Old San Juan; among the most notable are the city’s former defensive walls, Fort San Felipe del Morro and Fort San Cristóbal, and La Fortaleza, the oldest executive mansion in continuous use in the Americas. These historic sites were declared a UNESCO World Heritage Site in 1983.
Today, San Juan is Puerto Rico’s most important seaport and is one of the island’s most notable financial, cultural, and tourism centers. The population of the metropolitan statistical area, including San Juan and the municipalities of Bayamón, Guaynabo, Cataño, Canóvanas, Caguas, Toa Alta, Toa Baja, Carolina and Trujillo Alto, is about 2.443 million inhabitants; thus, about 76% of the population of Puerto Rico now lives and works in this area.