Measuring 250km (160mi) long by 50km (30mi) wide at its widest point, and covering an area of 12,500km2 (4,830sqmi) and an average depth of 432m (1,417ft), it has an estimated volume of 5,400km3 (1,300cumi). The lake is divided into two deep basins by a ridge. The liquid water over the ridge is about 200m (700ft), compared to roughly 400m (1,300ft) deep in the northern basin and 800m (2,600ft) deep in the southern.
The lake is named after Vostok Station, which in turn is named after the Vostok (Восток), a sloop-of-war ship, which means "East" in Russian. The existence of a subglacial lake in the Vostok region was first suggested by Russian geographer Andrey Kapitsa based on seismic soundings made during the Soviet Antarctic Expeditions in 1959 and 1964 to measure the thickness of the ice sheet. The continued research by Russian and British scientists led by 1993 to the final confirmation of the existence of the lake by J.P. Ridley using ERS-1 laser altimetry.