Lake Bonneville

Lake Bonneville was a prehistoric pluvial lake that covered much of North America's Great Basin region. Most of the territory it covered was in present-day Utah, though parts of the lake extended into present-day Idaho and Nevada. Formed about 32,000 years ago, it existed until about 14,500 years ago, when a large portion of the lake was released through the Red Rock Pass in Idaho. Following the Bonneville Flood, as the release is now known, the lake receded to a level called the Provo Level. Many of the unique geological characteristics of the Great Basin are due to the effects of the lake.

At more than 1,000 ft (300 m) deep and more than 19,691 square miles (51,000 km2) in area, the lake was nearly as large as Lake Michigan and significantly deeper. With the change in climate, the lake began drying up, leaving Great Salt Lake, Utah Lake, Sevier Lake, Rush Lake, and Little Salt Lake as remnants.

Lake Bonneville was named by the geologist G. K. Gilbert after Benjamin Louis Eulalie de Bonneville (1796–1878), a French-born officer in the United States Army, who was also a fur trapper, and explorer in the American West. Bonneville was noted for his expeditions to the Oregon Country and the Great Basin.