The United States possesses several territories in the Caribbean, the most significant being Puerto Rico and the U.S. Virgin Islands. Puerto Rico is an unincorporated territory and a commonwealth, home to over three million U.S. citizens who enjoy many benefits of citizenship but lack voting representation in Congress. The U.S. Virgin Islands consist of three main islands—St. Thomas, St. Croix, and St. John—along with several smaller islets; they were purchased from Denmark in 1917 for their strategic military value. Additionally, the U.S. maintains control over Navassa Island, a small, uninhabited tropical island currently managed as a National Wildlife Refuge, though its sovereignty is occasionally contested by Haiti. These islands serve as vital cultural and economic hubs for the U.S. in the region, offering domestic travel opportunities for American citizens (no passport required for those traveling from the mainland) and acting as key locations for maritime security and environmental research in the Caribbean Sea.