Lake Vostok is the biggest of the seventy lakes in Antarctica that are under sheets of ice. It is at 77° S 105° E. It is under Russia's Vostok Station. It is 4,000 meters (13,000 feet) under Antarctica's surface.
The lake was found by Russian and British scientists. They used radar to find it.
The lake consists of fresh water. The temperature of the water is about -3 °C. The freezing point of water is at 0 °C, but the water in the lake remains liquid because of the high pressure produced by the ice.
There are two separate basins in the lake. These are separated by a ridge. It has been suggested that the ecosystems of the two basins are different.