Long Island is an island in the U.S. state of New York. Stretching northeast from New York Harbor into the Atlantic Ocean, the island comprises four counties, including two that form the New York City boroughs of Brooklyn and Queens, and two that are farther out on the island and mainly suburban. Although all four counties are part of the greater New York metropolitan area, the name "Long Island" is often incorrectly used to refer to only Nassau and Suffolk counties, as distinct from the counties lying within New York City proper. North of the island is Long Island Sound, across which are the states of Connecticut and Rhode Island.
With a Census-estimated population of 7,740,208 in 2013, embodying nearly 40% of New York State's population, Long Island is the most populated island in any U.S. state or territory, and the 17th-most populous island in the world. Its population density is 5,402 inhabitants per square mile. If it were a U.S. state, Long Island would rank 13th in population and first in population density.