Lahontan, Lake

Vast body of water – now largely dried out – that late in the last Ice Age occupied an area of some 22,000 sq km/8,500 sq mi in northwestern Nevada and northeastern California. It is thought to have been around 275 m/900 ft deep. Lake Lahontan disappeared gradually from about 15,000 years ago; today, its largest vestiges include Pyramid, Walker, and Winnemucca lakes and the Carson Sink.

The original lake extended north to near the Idaho–Nevada border, south to just below Walker Lake, and west to the Sierra Nevada. It was irregularly shaped, and was replenished by rains generated by the glacial front that at the time lay immediately to the north. To the east, Lake Bonneville was more than twice its current size. Archaeological sites along Lake Lahontan's former shoreline, such as that at Lovelock Cave, testify to the presence of humans there as long as 10,000 years ago. The Carson, Humboldt, and Truckee rivers and the Black Rock Desert are all in the area once once occupied by Lake Lahontan.