Long Island is an island located in southeastern New York, United States, just east of Manhattan. Stretching northeast into the Atlantic Ocean, Long Island contains four counties, two of which are boroughs (Queens and Brooklyn) of New York City, and two of which (Nassau and Suffolk) are mainly suburban. Numerous bridges and tunnels through Brooklyn and Queens connect Long Island to the three other boroughs of New York City. Ferries connect Suffolk County northward across Long Island Sound to the state of Connecticut.

Both the longest[1] and the largest island in the contiguous United States, Long Island extends 118 miles (190 km) from New York Harbor, and has a maximum width of 23 miles (37 km) between the northern (Long Island Sound) coast and the southern Atlantic coast.[2] With an area of 1,401 square miles (3,629 km2), Long Island is the 11th largest in the United States, and the 148th largest island in the world. The land area of Long Island is larger than that of the state of Rhode Island and larger than any U.S. territory except Puerto Rico.[2]

Long Island had a population of 7,448,618 as of the 2000 census,[2] with the population estimated at 7.7 million as of July 1, 2008,[citation needed] making it the most populated island in any U.S. state or territory. It is also the 17th most populous island in the world, ahead of Ireland, Jamaica and the Japanese island of Hokkaidō. Its population density is 5,470 inhabitants per square mile (2,110 /km2). If it were a state, Long Island would rank 12th in population.