Puerto Rico became part of the United States in 1898, after the Spanish–American War, and was formally made a U.S. territory in 1917.

Key dates

  • 1898: Spain ceded Puerto Rico to the U.S. in the Treaty of Paris at the end of the Spanish–American War, and U.S. forces formally took control of the island that year.
  • 1917: The Jones–Shafroth Act declared Puerto Rico a U.S. territory and granted U.S. citizenship to Puerto Ricans born on or after April 25, 1898.
  • 1952: Puerto Rico adopted its own constitution and became a U.S. commonwealth with a degree of self‑government, while still remaining a U.S. territory.

Quick context

  • Puerto Rico is not a U.S. state; it is an unincorporated U.S. territory with commonwealth status.
  • People born in Puerto Rico are U.S. citizens and can move freely to the mainland United States, but the island has no voting representation in the U.S. Congress and residents cannot vote in U.S. presidential elections unless they live in a state.

TL;DR: When people ask “when did Puerto Rico become part of the US,” historians usually point to 1898 for U.S. takeover and 1917 for formal territorial status and citizenship.

Information gathered from public forums or data available on the internet and portrayed here.