In an average year the lake covers an area of around 1,700 square miles (4,400 km2), but the lake's size fluctuates substantially due to its shallowness. For instance, in 1963 it reached its lowest recorded size 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 km2). 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 prehistoric pluvial lake that once covered much of western Utah. The three major tributaries to the lake, the Jordan, Weber, and Bear rivers together deposit around 1.1 million tons of minerals in the lake each year.
As it is endorheic (has no outlet besides evaporation), it has very high salinity (far saltier than seawater) and its mineral content is steadily increasing. Due to the high density resulting from its mineral content, swimming in the Great Salt Lake is similar to floating. Its shallow, warm waters cause frequent, sometimes heavy lake-effect snows from late fall through spring.
Although it has been called "America's Dead Sea", the lake provides habitat for millions of native birds, brine shrimp, shorebirds, and waterfowl, including the largest staging population of Wilson's phalarope in the world.
According to wikipedia