Indonesia is home to 521 natural lakes and about 100 reservoirs, covering an area of approximately 21,000 km². The total volume of water held across the country is approximately 500 km³. The largest lake, by both area and volume, is Lake Toba in Sumatra. It holds about 240 km³ of freshwater, and is the largest lake body in Southeast Asia.Lake Toba is an immense volcanic lake covering an area of 1,707 km², making it even bigger than Singapore.