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. In popular usage, however, the term “Long Island” generally refers only to Nassau and Suffolk counties in order to differentiate them from New York City.
Long Island had a population of 7,448,618 as of the 2000 census, 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 Hokkaido. 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.
Both the longest 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. With a land area of 1,401 square miles (3,629 km2), Long Island is the 11th largest island in the United States, the 148th largest island in the world, larger than any U.S. territory except Puerto Rico, and just smaller than the state of Rhode Island (1545 sq mi). Nine bridges and 13 tunnels (including railway tunnels) connect Brooklyn and Queens (and thus 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. Two of New York City's major airports, La Guardia and JFK, are located on Long Island, in Queens.