Bonneville Salt Flats

The Bonneville Salt Flats lie in Tooele County in northwestern Utah, spanning about 19 kilometers long and 8 kilometers wide for a total area of roughly 100 square kilometers, at an elevation of 1,291 meters. The flats are a remnant of Pleistocene-age Lake Bonneville, a vast ancient lake that once covered much of the region; as the lake dried up, it left behind a thick deposit of concentrated salt. The crust reaches nearly 1.5 meters thick at the center of the flats but thins to less than 2.5 centimeters near the edges, and the salt pan is estimated to hold about 147 million tons of salt, roughly 90 percent of it ordinary sodium chloride. This entity documents the Bonneville Salt Flats specifically as a geological formation, an evaporite deposit left behind by a drying Pleistocene lake.