Puerto Rico (Spanish for 'rich port'; abbreviated PR; Taino: Boriken, Borinquen), officially the Commonwealth of Puerto Rico (Spanish: Estado Libre Asociado de Puerto Rico, lit. 'Free Associated State of Puerto Rico'), is a Caribbean island and unincorporated territory of the United States with official Commonwealth status. It is located in the northeast Caribbean Sea, approximately 1,000 miles (1,600 km) southeast of Miami, Florida, between the Dominican Republic and the U.S. Virgin Islands, and includes the eponymous main island and several smaller islands, such as Mona, Culebra, and Vieques. It has roughly 3.2 million residents, and its capital and most populous city is San Juan. Spanish and English are the official languages of the executive branch of government, though Spanish predominates.

Puerto Rico was settled by a succession of indigenous peoples beginning 2,000 to 4,000 years ago; these included the Ortoiroid, Saladoid, and Taíno. It was then colonized by Spain following the arrival of Christopher Columbus in 1493. Puerto Rico was contested by other European powers, but remained a Spanish possession for the next four centuries. An influx of African slaves and settlers primarily from the Canary Islands and Andalusia vastly changed the cultural and demographic landscape of the island. Within the Spanish Empire, Puerto Rico played a secondary but strategic role compared to wealthier colonies like Peru and New Spain. By the late 19th century, a distinct Puerto Rican identity began to emerge, centered around a fusion of indigenous, African, and European elements. In 1898, following the Spanish–American War, Puerto Rico was acquired by the United States.

Puerto Ricans have been U.S. citizens since 1917, and can move freely between the island and the mainland. However, as residents of an unincorporated territory, American citizens of Puerto Rico are disenfranchised at the national level, do not vote for the president or vice president, and generally do not pay federal income tax. In common with four other territories, Puerto Rico sends a nonvoting representative to the U.S. Congress, called a Resident Commissioner, and participates in presidential primaries; as it is not a state, Puerto Rico does not have a vote in Congress, which governs it under the Puerto Rico Federal Relations Act of 1950. Congress approved a local constitution in 1952, allowing U.S. citizens residing on the island to elect a governor. Puerto Rico's current and future political status has consistently been a matter of significant debate.

Beginning in the mid-20th century, the U.S. government, together with the Puerto Rico Industrial Development Company, launched a series of economic projects to develop Puerto Rico into an industrial high-income economy. It is classified by the International Monetary Fund as a developed jurisdiction with an advanced, high-income economy; it ranks 40th on the Human Development Index. The major sectors of Puerto Rico's economy are manufacturing (primarily pharmaceuticals, petrochemicals, and electronics) followed by services (namely tourism and hospitality).