Lake Sevan is the largest lake in Armenia and the Caucasus region. It is one of the largest fresh-water high-altitude lakes in the world.
Lake Sevan is situated in the central part of the Republic of Armenia, inside the Gegharkunik Province, at the altitude of 1,900m above sea level. The total surface area of its basin is about 5,000 km2, the lake itself is 940 km2, and the volume is 34.0 bln cubic metres. It is fed by 28 rivers and streams. Only 10% of the outgoing water is drained by the Hrazdan (Razdan) river, while the remaining 90% evaporates.
Before human intervention dramatically changed the Lake Sevan ecosystem, the lake was 95 metres deep, covered an area of 1,360 km^(2) (5% of Armenia's entire area), had a volume of 58 km^(3) and a perimeter of 260 km. The lake surface was at an altitude of 1,916 m above sea level.
Along with Lake Van and Lake Urmia, Sevan was considered one of the three great lakes of the historical Armenian Kingdom, collectively referred to as the Seas of Armenia; it is the only one within the boundaries of today's Republic of Armenia. The Sevanavank peninsula (formerly an island) is the historic area of the lake at its northern shores.