Capitol of Puerto Rico in the context of "House of Representatives of Puerto Rico"

San Juan Islet (Spanish: Isleta de San Juan) is a 3-square-mile (7.8 km) islet or small island on San Juan Bay in the Atlantic coast of northern Puerto Rico. Home to Old San Juan, it is the site of the oldest permanent European settlement in Puerto Rico (1521), and the second-oldest European settlement in the West Indies after Santo Domingo (1496). Due to its strategic location in the Caribbean during the Spanish colonization of the Americas, it is home to a city wall and a number of militaristic buildings such as El Morro Castle. Today, it is also home to many of Puerto Rico's government buildings such as the territory's capitol building (El Capitolio).

La Fortaleza (English: "the fortress"), officially the Palacio de Santa Catalina ("Saint Catherine's Palace"), is the official residence and workplace of the governor of Puerto Rico. Located in the historic quarter of Old San Juan in the capital municipality of San Juan, it has served as the governor’s residence since the 16th century, making it the oldest executive mansion in continuous use in the New World. Built as a medieval fortress from 1533 to 1540 by orders of King Charles I of Spain, and remodeled to its present Neoclassical style in 1846 by orders of Governor Rafael Arístegui y Vélez, it was the first fortification erected by the Spanish on San Juan Islet to defend San Juan Bay, the harbor of Old San Juan. Alongside El Morro, San Cristóbal, and other forts part of the Walls of Old San Juan, it protected strategically and militarily important Puerto Rico, or La Llave de las Indias (The Key to the Indies), from invasion by competing world powers and harassment by privateers and pirates during the Age of Discovery and Sail. It was designated a World Heritage Site in 1983.

Situated in the western end of San Juan Islet in the Old San Juan historic quarter, La Fortaleza, seat of the executive branch, is about 1 mile (1.6 km) from the Capitol of Puerto Rico, seat of the legislative branch, in the center of the Islet in the Puerta de Tierra historic district, and 2 miles (3.2 km) from the Supreme Court Building, seat of the judicial branch, in the eastern end of the Islet in Puerta de Tierra.

The Supreme Court Building (Spanish: Edificio del Tribunal Supremo) is the seat of the Supreme Court of Puerto Rico, the highest court of the judicial branch in the U.S. territory, located within the grounds of the Luis Muñoz Rivera Park in the Puerta de Tierra historic district of San Juan, the capital municipality. Built by the Toro Ferrer firm in 1955, the Tropical Modern, International Style courthouse is a three-story, rectangular edifice projected over a perpendicular reflecting pool. Situated in the eastern end of San Juan Islet, it is about 1 mile (1.6 km) from the Capitol, seat of the legislative branch, in the center of the Islet near the entrance to the Old San Juan historic quarter, and 2 miles (3.2 km) from the La Fortaleza, seat of the executive branch, in the western end of the Islet in Old San Juan. It was listed on the U.S. National Register of Historic Places in 2006.

The Supreme Court building is home to the Supreme Court of Puerto Rico, the highest court in the archipelago and island, and is the successor to the Real Audiencia Territorial (Royal Territorial Court), a court of appeals with jurisdiction over Puerto Rico first founded by the Spanish Empire in 1832. Its construction marked the newly established commonwealth status of Puerto Rico, which was specified in the Constitution of Puerto Rico in 1952. The building was officially inaugurated in February 1956 with U.S. Supreme Court chief justice Earl Warren as the main speaker.