Fire Island is a barrier island, approximately 31 miles (50 km) long and varying between approximately 0.1 mile (160 m) to 0.25 mile (400 m) wide. Fire Island passes through southern Suffolk County, New York, and is southeast of Long Island separated from the main land by the Great South Bay in the U.S. state of New York, running approximately SW to NE. The land area is 8.687 sq. mi. (22.5 km2), and a permanent population of 491 people was reported as of the 2000 census. (There are hundreds of thousands of summertime residents, groupers and daytrippers.) The island is composed of three communities, as defined by the Census Bureau. The largest of these is Fire Island (CDP), which is unincorporated and stretches through the southern portion of the towns of Babylon, Islip, and Brookhaven.