Lake Sevan (Armenian: Սևանա լիճ ) is the largest lake in Armenia and the Caucasus region. It is one of the largest freshwater high-altitude lakes in the world.
Lake Sevan is situated in the central part of the Republic of Armenia, in the Gegharkunik Province, at the altitude of 1,900 m (6,200 ft) above sea level. The total surface area of its basin is about 5,000 km2 (1,900 sq mi), the lake itself is 940 km2, and the volume is 34.0 billion m3. 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 m (312 ft) deep, covered an area of 1,360 km² (5% of Armenia's entire area), had a volume of 58 km³ and had 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 Sevanpeninsula (formerly an island) is home to a medieval monastery.