; Washo: dáʔaw) is a large freshwater lake in the Sierra Nevada of the United States.
Lying at 6,225 ft (1,897 m), it straddles the state line between California and Nevada, west of Carson City.
The West Tahoe Fault appears to be the most active and potentially hazardous fault in the basin.
A study in Fallen Leaf Lake, just south of Lake Tahoe, used seafloor mapping techniques to image evidence for paleoearthquakes on the West Tahoe and revealed the last earthquake occurred between 4,100 and 4,500 years ago.
Uplifted blocks created the Carson Range on the east and the main Sierra Nevada crest on the west.The Lake Tahoe Watershed (USGS Huc 18100200) of 505 sq mi (1,310 km) includes the land area that drains to the lake and the Lake Tahoe drainage divide traverses the same general area as the Tahoe Rim Trail. These drain an area about the same size as the lake and produce half its water, with the balance entering as rain or snow falling directly on it.The Truckee River is the lake's only outlet, flowing northeast through Reno, Nevada, into Pyramid Lake which has no outlet.Down-dropping and block tilting (half-grabens) created the Lake Tahoe Basin in between.This kind of faulting is characteristic of the geology of the adjoining Great Basin to the east.