Despite the fact that Long Island is surrounded by water on all sides, the United States Supreme Court unanimously decided in 1985 that Long Island is a peninsula, not an island. The case in question, United States v. Maine, developed from disputes between states and the federal government over who has legal authority over the water between the eastern tip of Long Island and Block Island Sound. If Long Island was an island, it was argued, then the federal government would control the waterways. If it was a peninsula, the rights would belong to the states. In the end, the court ruled in favor of the states, declaring that Long Island is an extension of the New York mainland, and thus not a natural island.
