No, St. Maarten/St. Martin is not owned by the United States. The island is unique because it is divided between two different European nations. The southern part, Sint Maarten, is a constituent country within the Kingdom of the Netherlands. The northern part, Saint-Martin, is an overseas collectivity of France. This 37-square-mile island represents the smallest landmass in the world shared by two sovereign nations. While the U.S. Dollar is widely accepted as a primary currency and the island is a major destination for American tourists and cruise ships, it has no political ties to the U.S. government. Travelers should note that while there are no hard borders between the Dutch and French sides, they have different telecommunications systems, laws, and official languages (Dutch/English in the south, French in the north). If you are looking for a U.S. territory in the Caribbean, you would be thinking of the U.S. Virgin Islands (St. Thomas, St. Croix, and St. John) or Puerto Rico.