Remains of a small indigenous fishing village have been found in Puerta de Tierra where the Puerto Rico National Guard Museum stands today, however most archaeological sites in the region have been destroyed and lost throughout the colonial history.

[9] The area of San Juan used to be the boundary between the tribal regions (yucayeques) of Guaynabo and Haimanio, led by the chiefs (caciques) Mabo and Yuisa (also known as Loaíza), respectively, at the time of the arrival of the Spanish conquistadors.

Various events and circumstances, including liberalized commerce with Spain, the opening of the island to immigrants as a direct result of the Royal Decree of Graces of 1815, and the colonial revolutions, led to an expansion of San Juan and other Puerto Rican settlements in the late 18th and early 19th century.

All military actions in Puerto Rico were suspended August 13, 1898, after President William McKinley and French Ambassador Jules Cambon, acting on behalf of the Spanish government, signed an armistice.

[30] Marxuach, who was a member of the "Porto Rico Regiment of Infantry" and Officer of the Day, on March 25, 1915, opened fire on the Odenwald, an armed German supply vessel, when it was trying to force its way out of San Juan's bay.

At the time, the area was used by the military as an air base and it was also Puerto Rico's first commercial airport, and Rigau Carrera was allowed to perform his historic flight from the airfield.

[34] During the Cold War era, she ordered the establishment of the island's first Civil Defense system under the directorship of Colonel Gilberto José Marxuach (Teófilo's son).

The damage caused in 2017 was extensive, affecting the electricity, potable water supplies, transportation, and communication, but significant progress had been made in the capital by April 2019, and particularly by October 2019.

[48] As with other parts of Puerto Rico and the Caribbean, San Juan is often blanketed by waves of Saharan dust coming from the Sahara across the Atlantic Ocean in Northern Africa.

Its main attraction is the cableway that crosses the park and offers scenic views of the Piedras River and the city while providing transportation to the Roberto Clemente Coliseum and the Hiram Bithorn Stadium.

[90] The University of Puerto Rico, Río Piedras Campus is also home to a rich variety of buildings that showcase the history of Puerto Rican architecture throughout the past 120 years, with buildings designed by notable architects such as Frank Lloyd Wright's student Henry Klumb, Edward H. Bennett, William E. Parsons,[91] and Rafael Carmoega who designed the distinctive clock tower and the university quadrangle, both of which were inscribed in the NRHP in 1984.

The small island, which comprises an area of 47 square miles (120 km2), also hosts the working-class neighborhood of Puerta de Tierra and most of Puerto Rico's central government buildings, including the Commonwealth's Capitol.

[95] Other buildings of interest predating the 18th century are the Ayuntamiento or Alcaldía (San Juan City Hall), the Diputación Provincial and the Real Intendencia buildings, which house the Puerto Rico Department of State,[96] the Casa Rosa, the San José Church (1523) and the adjacent Hotel El Convento, the former house of the Ponce de León family known as Casa Blanca, the Teatro Tapia, the former Spanish barracks (now Museum of Ballajá), La Princesa (former municipal jail, now headquartering the Puerto Rico Tourism Company), and the Santa María Magdalena de Pazzis Cemetery, located just outside the city walls.

[100] Old San Juan, also known as the "old city", is the main cultural tourist attraction in Puerto Rico; its bayside is lined by dock slips for large cruise ships.

[101] Santurce, originally named San Mateo de Cangrejos (Saint Matthew of the Crabs), was a settlement for freed African slaves during the early days of the city.

At the beginning of the twentieth century an electric trolley was installed, the township was split into three parts, and its main settlement, merged with the city, was renamed using the Spanish spelling of Santurtzi (Saint George in Basque), Ubarri's birthplace in Vizcaya, Spain.

Hato Rey was grazing ground for cattle owned by the royal government (hence its name, the King's Herd in Spanish) as early as the 16th century,[105] and is now considered the financial center of the island.

Its strategic location south of the capital served as a junction for all the principal ways of transportation of the island and as a geographical entry to San Juan, which are factors that prompted Río Piedras's dramatic urban development in the 20th century.

The district of Hato Rey contains a corporate sector known as Milla de Oro (Golden Mile) which serves as the headquarters of local and international banks.

[120] Other companies based in San Juan include ATH Network, First BanCorp, Liberty Puerto Rico, The Cervantes Group, and Triple-S Management Corporation.

[123] Old San Juan is often emphasized in tourism campaigns, promoting the historic nature of its colonial buildings and narrow streets covered by cobblestones, a blue stone cast from furnace slag; they were brought over as ballast on Spanish ships.

[125] The PRCC District also hosts a number of hotels, nightclubs, shops, cinemas, bars and restaurants,[126] the Coca-Cola Music Hall, and the Toro Verde Eco Adventure Park.

The University of Puerto Rico's main campus in Río Piedras is also of interest with its historic quadrangle and clock tower, its number of theaters and venues which host events such as the Casals Festivals, and a museum.

During the 20th century, the musical aspect of the city was influenced by performers including Afro-Caribbean dancer and choreographer Sylvia del Villard and José Enrique Pedreira who became a composer of Puerto Rican Danzas.

International musicians such as opera singer Justino Díaz and Grammy Award winners Ramón Ayala (Daddy Yankee) and Ricky Martin were born in the city.

Other notable residents include writers Giannina Braschi and Tomas Blanco, award-winning actors Raul Julia and Benicio del Toro, and comedian José Miguel Agrelot.

The event, originally a community festival coinciding with the feast day of Saint Sebastian, has become an important part of Puerto Rican popular culture, being unofficially considered to mark the end of the Christmas and holiday season in the island.

Concha Melendez Ramirez in Santurce is a National Historic Landmark and museum and research center that showcases the life and work of one of the most important figures in the literary culture of Puerto Rico.

These schools emphasize topics such as Science and Math, Radio and Television, Arts, Trade, Music, and Sports, but also include other subjects such as Spanish, English, and Social Studies in their curriculum.

The plans for redevelopment also hope to make the city more appealing in order to attract new residents, as San Juan has suffered from a shrinking population over the past 60 years.