Long Island is an island in the U.S. state of New York. Stretching northeast into the Atlantic Ocean, Long Island contains four counties, two of which, (Brooklyn and Queens), are boroughs of New York City, and two of which are mainly suburban (Nassau and Suffolk). In popular usage, “Long Island” often refers only to Nassau and Suffolk counties in order to differentiate them from New York City, although all four counties are on the island and part of the New York metropolitan area.
As of the 2010 census, Long Island had a population of 7,568,304, 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 5,402 inhabitants per square mile (2,086 /km2). If it were a state, Long Island would rank 13th in population (after Virginia) and first in population density.
Both the longest and the largest island in the contiguous United States, Long Island extends 118 miles (190 km) eastward from Upper New York Bay to Montauk Point, and has a maximum north-to-south expanse 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 and the 148th-largest island in the world — larger than the 1,214 square miles (3,140 km2) of the smallest state, Rhode Island.
Two of New York City’s major airports, LaGuardia Airport and JFK International Airport, are located on Long Island, in Queens. 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.