The Great Salt Lake, located in the northern part of the U.S. state of Utah, is the largest salt water lake in the western hemisphere, and the fourth-largest terminal lake in the world. In an average year the lake covers an area of around 1,700 square miles (4,400 km square), but the lake's size fluctuates substantially due to its shallowness. For instance, in 1963 it reached its lowest recorded level at 950 square miles (2,460 km²), but in 1988 the surface area was at the historic high of 3,300 square miles (8,500 km square). In terms of surface area, it is the largest lake in the United States that is not part of the Great Lakes region.
The lake is the largest remnant of Lake Bonneville, a pluvial lake which covered much of western Utah in prehistoric times. The Great Salt Lake is endorheic (has no outlet besides evaporation) and has very high salinity, far saltier than sea water. The Jordan, Weber, and Bear rivers (the three major tributaries) deposit around 1.1 million tons of minerals in the lake each year, and since water (but not the minerals) is constantly being evaporated, the concentration of minerals increases further. Because of its unusually high salt concentration, most people can easily float in the lake as a result of the higher density of the water, particularly in the saltier north arm of the lake, Gunnison Bay. The lake's shallow, warm waters cause frequent, sometimes heavy lake-effect snows during late fall, early winter, and spring.
The Great Salt Lake lends its name to Salt Lake City, originally named "Great Salt Lake City" by the President of the Church of Jesus Christ of Latter-day Saints (known as the Mormon or LDS Church) Brigham Young, who led a group of Mormon pioneers to the Salt Lake Valley southeast of the lake on July 24, 1847.
Salt Lake City and its suburbs are located to the southeast and east of the lake, between the lake and the Wasatch Mountains, but land around the north and west shores is almost uninhabited. The Bonneville Salt Flats lie to the west, and the Oquirrh and Stansbury Mountains rise to the south.
Categorically stating the number of islands is difficult, as the method used to determine what is an island is not necessarily the same in each source. Since the water level of the lake can vary greatly between years, what may be considered an island in a high water year may be considered a peninsula in another, or an island in a low water year may be covered during another year. According to the U.S. Department of the Interior and the U.S. Geological Survey, "there are eight named islands in the lake that have never been totally submerged during historic time. All have been connected to the mainland by exposed shoals during periods of low water." In addition to these eight islands, the lake also contains a number of rocks, reefs, or shoals that become fully or partially submerged at high water levels.
The Utah Geological Survey, on the other hand, states "the lake contains 11 recognized islands, although this number varies depending on the level of the lake. Seven islands are in the southern portion of the lake and four in the northwestern portion."
The size and whether they are counted as islands during any particular year depends mostly on the level of the lake. From largest to smallest, they are Antelope Island, Stansbury Island, Fremont Island, Carrington Island, Dolphin Island, Cub Island, and Badger Island, and various rocks, reefs, or shoals with names like Strongs Knob, Gunnison Island, Goose, Browns, Hat (Bird), Egg Island, Black Rock, and White Rock. Dolphin Island, Gunnison Island, Cub Island, and Strongs Knob are in the northwestern arm. The rest are in the southern portion of the Great Salt Lake.