Long Island (1990 pop. 6,861,454), 1,723 sq mi (4,463 sq km), 118 mi (190 km) long, and from 12 to 20 mi (19–32 km) wide, SE N.Y.; fourth largest island of the United States and the largest outside Alaska and Hawaii. It is separated from Staten Island by the Narrows, from Manhattan and the Bronx by the East River, and from Connecticut by the Long Island Sound; on the south is the Atlantic Ocean. Long Island comprises four counties—Kings, Queens, Nassau, and Suffolk; Kings (coextensive with Brooklyn) and Queens are part of New York City.
Eastern Long Island has two flukelike peninsulas that are separated by Peconic Bay. The northern fluke, terminating in Orient Point, follows part of the Harbor Hill moraine, a hilly ridge that extends west along N Long Island to the Narrows and was deposited by melting ice during the last stage of the Pleistocene period. The southern fluke, terminating in Montauk Point, follows the Ronkonkoma moraine, a somewhat older morainal ridge that extends west to join the Harbor Hill moraine at Lake Success. Low, wooded hills, capped by glacial deposits lie north of the moraines and contrast with a broad, low-lying outwash plain to the south; the highest point on the island is c.400 ft (120 m) above sea level. Long beaches, backed by dunes and shallow lagoons, fringe the south shore; the north shore has low cliffs and is deeply indented by bays.
With no large streams, water supply is limited and is obtained from groundwater or from reservoirs on the mainland. Large recharge basins catch surplus rainwater to replenish underground supplies, and strict conservation measures have been imposed to prevent further contamination of groundwater from sewage disposal and detergents and from encroachment by seawater.
Both the Dutch and the English established farming, whaling, and fishing settlements on Long Island, but it remained sparsely settled until railroads, bridges, and highways provided easy access to New York City. The Long Island Expressway is particularly high-trafficked. Industrial and residential growth occurred rapidly after World War II, and in the 1970s and 80s development further intensified. Farming has declined in importance and changed in nature over time in E Long Island; fields of potatoes have been replaced in part by housing developments and by wine grapes and other more lucrative crops. Sand and gravel are quarried from the island's glacial deposits. Sport and commercial fishing is important on the south and east coasts. The south shore, a popular recreational area, includes Fire Island National Seashore, Robert Moses and Jones Beach state parks, Coney Island, and parts of Gateway National Recreation Area. The Hamptons are an affluent residential and beach community.
La Guardia and John F. Kennedy International airports are on W Long Island; the Brookhaven National Laboratory is in the east. Among the many higher-education institutions are the State Univ. of New York campuses at Stony Brook and Westbury, Long Island Univ., Adelphi Univ., Hofstra Univ., and branches of New York City universities.
In 1995 a state law was signed resolving the highly contentious issue of development of the 100,000-acre (40,500-hectare) Pine Barrens on E Long Island. A forest preserve was established, with a core of 52,500 acres (21,260 hectares) in which development would cease or be severely limited and a surrounding area in which development would be regulated and assisted. In 1997 an agreement was reached to preserve the remains of a 400-year-old fort built by Cutchogue Indians.
See B. Bookbinder, Long Island (1983); M. Tucker, ed., Long Island Writers & Writings (1985).