The lake is situated within the Western Rift of the Great Rift Valley and is confined by the walls of the valley. It is the largest rift lake in Africa and the second largest lake on the continent. It is the deepest lake in Africa and holds the greatest volume of fresh water. It extends for 673km in a general north-south direction and averages 50km in width. The lake covers 32,900 km², with a shoreline of 1,828km and a mean depth of 570m and a maximum depth of 1,470m (in the northern basin) it holds an estimated 18,900 km³. The enormous depth of the lake means that much of the lower level of the lake are so-called 'fossil water'. The catchment area of the lake covers 231,000 km², with the main river flowing into the lake the Ruzizi River entering the north of the lake.
The lake has a remarkable variety of fish fauna, much of it unique, it holds at least 300 species of cichlid fish and six non-cichlid species. Almost all the cichlid species found there are Endemic to the lake.
The lake has, naturally, been a source of food for local peoples throughout their existence, currently there are around 45,000 people directly involved in the fisheries operating from almost 800 sites, there around 1 million people dependent on the fishers. Commercial fishing began in the mid-1950s and has had an extremely heavy impact of the majority of fish species, in 1995 the total catch was around 180,000 tonnes.
The lake was first discovered by Europeans in 1858 when the explorers Richard Burton and John Speke reached it while exploring for the source of the Nile River. Speke continued and found the actual source, Lake Victoria.