Long Island is not an island.
While the definition of an island is a body of land that is surrounded by water on all sides, the Supreme Court of the United States ruled otherwise. In US v. Maine, 469 U.S. 504 (1985), it unanimously held that Long Island is an extension of the mainland – a peninsula. A New York Times story satirically reported on the case. Here is a link to the story — tinyurl.com/SCTLI