Puerto Rico is a territory of the United States. A U.S. territory is an area that belongs to the United States but is not a state.  Territories don’t have the powers and rights possessed by states.  The power of Congress over territories is exclusive and complete, as described under Article IV of the Constitution:

The Congress shall have the power to dispose of and make all needful rules and regulations respecting the territory or other property belonging to the United States.

A piece of land belonging to the United States can be only a territory or a state under U.S. law.

Puerto Rico became a U.S. territory in 1898, when it was acquired from Spain after the Spanish-American War.  With approximately 3.7 million residents, it is the most highly populated of all United States territories.

 Why are people sometimes confused over whether Puerto Rico is a territory?

Some people claim that a law passed by Congress in 1952 changed Puerto Rico’s Constitutional status from a territory to a “Commonwealth.”  The term “commonwealth” has no special legal status in the United States; for example, Kentucky is a commonwealth and also a state, but this doesn’t make Kentucky different from Louisiana in its relationship to the Federal Government. Read more about this issue.

Read original authoritative sources confirming that Puerto Rico remains a territory of the United States.