After being under colonial Spanish rule for 405 years, the island of Puerto Rico became a colony of the United States in 1898. In 1917, Puerto Ricans were granted US citizenship, allowing them to move freely between the island and the mainland without a passport. However, Puerto Rican migration to the United States did not begin in earnest until the 1950s, facilitated by the advent of air travel. Initially, most Puerto Ricans settled in East Coast cities like New York, Boston, and Philadelphia, creating enclaves that sometimes grew to cover entire neighborhoods. They were the first Hispanic group to migrate to the United States in large numbers. Today, more Puerto Ricans live in the continental United States than on the island of Puerto Rico.

After centuries of colonial rule and exploitation, Puerto Rico suffers from economic instability and high rates of poverty, which drives migration. These issues have been compounded by modern-day difficulties of natural disasters, the debt crisis, and the COVID-19 pandemic. The island remains a territory of the United States. Its residents are citizens; they can serve in the military and are subject to federal laws but cannot vote in general elections and lack full representation in Congress. This remains a controversial relationship, and many argue for a change, such as making the island a US state or allowing the territory greater independence.