A territory of the United States, Puerto Rico is an island among the Greater Antilles, and ranked third of the four in terms of population. It has a tropical climate and has problems with Atlantic hurricane season.
Originally occupied by the Spanish, the native population was nearly wiped out. What was left was emancipated a generation later, but Spain continued to control the island for four centuries afterward, culminating in a desperate decree in 1815. Under the Treaty of Paris from the Spanish-American War, the island was ceded from Spain to the United States. In 1917 Puerto Rico citizens became official United States citizens. Puerto Rico consists of the proper island in addition to many smaller islands as well.
There are many aspects of Puerto Rico life controlled ultimately by the US government, but there are many exceptions. Among these, residents cannot vote in federal elections. They weren't allowed to vote for their own governor until 1947.