Fire Island is a 5.5-mile (8.9 km) long island in the U.S. state of Alaska, located near the head of Cook Inlet at 61°09′34″N 150°11′55″W / 61.1594444°N 150.1986111°WCoordinates: 61°09′34″N 150°11′55″W / 61.1594444°N 150.1986111°W. It is the only island in the Municipality of Anchorage, sitting three miles (5 km) off the city's Point Campbell, and nine miles (14.5 km) from downtown. Its land area is 17.467 km2 (6.7439 sq mi, or 4,316.1 acres), and there was no permanent resident population at the 2000 census.
Fire Island is underlain by sedimentary rocks, atop which lie deep sand and gravel deposits from the surrounding tidal estuary. The island is ringed by steep bluffs that average about 60 metres (200 ft) high, and the land elevation ranges from 25–90 above sea level. At low tide, it is possible to walk across the mud flats of the Cook Inlet to reach Fire Island. Hikers occasionally attempt the 3.5-mile (5.6-km) trek from Kincaid Park, but the incoming tide can make the journey dangerous, and people have been known to drown.