Lake Toba (Indonesian: Danau Toba) is a lake and supervolcano. The lake is 100 kilometres long, 30 kilometres wide, and up to 505 meters (1,666 ft) deep. Located in the middle of the northern part of the Indonesian island of Sumatra with a surface elevation of about 900 metres (2,953 ft).
It is the largest lake in Indonesia and the largest volcanic lake in the world.