Bonneville, Lake, a prehistoric freshwater lake that once covered northwestern Utah and adjoining parts of Idaho and Nevada. At its maximum extent, during the last Ice Age, the lake covered roughly 20,000 square miles (52,000 km2) and was as much as 1,000 feet (300 m) deep. Drainage was northward to the Snake River. Present-day remnants of the lake include the Great Salt Lake and Utah Lake.
Lake Bonneville was named for Benjamin Louis Eulalie Bonneville (1796–1878), a United States explorer. Many world automobile speed records have been set on the lake's bed near Wendover, Utah—the Bonneville Salt Flats.