San Juan, Puerto Rico, the commonwealth's capital and largest city. It lies on the northeastern coast along the Atlantic Ocean, some 1,025 miles (1,650 km) southeast of Miami. The center and oldest part of the city, including the section called Old San Juan, is on a small island at the entrance to San Juan Bay. Several bridges connect this island with the rest of the city.

San Juan is the commercial, financial, and industrial center of Puerto Rico. The tourist and convention trade, which has greatly increased since the early 1960's, is one of the mainstays of the city's economy. Industries include rum distilling, sugar refining, and the manufacturing of metal products, electrical goods, drugs, and chemicals. San Juan's well-equipped port handles much of Puerto Rico's overseas trade. Railways, ocean liners, modern highways, and an international airport serve the city.

Much of San Juan has modern commercial and residential buildings and wide avenues. In contrast is historic Old San Juan with its narrow streets and Spanish colonial buildings. The most imposing landmarks here are the fortresses of El Morro (16th century) and San Cristóbal (17th century). Casa Blanca and the Church of San José, built in the early 1500's, are among the oldest buildings in continuous use in the Americas. La Fortaleza, the residence of Puerto Rico's governors for more than 400 years, dates to 1533. In San Juan Cathedral is the tomb of Ponce de León.

Other attractions in San Juan include the Plaza de Colón, with an imposing statue of Columbus; the white marble capitol building; and numerous art and historical museums. Two campuses of the University of Puerto Rico are in or near the city.

San Juan was founded in 1521 after Ponce de León's original settlement across San Juan Bay was abandoned. The city was quickly fortified to resist attacks by privateers. It was occupied briefly by the English in 1598 and by the Dutch in 1624. San Juan stagnated under restrictive colonial policies from the early 1600's until 1815, when Spain permitted free trade with foreign ports and opened Puerto Rico to immigration and settlement. In 1898, during the Spanish-American War, United States troops captured the city. San Juan's modern development began in the 1940's with “Operation Bootstrap,” a program to diversify and strengthen the Puerto Rican economy.

Population: 437,745.