Lake Sevan In Armenia is the important lake. Lake Sevan is the largest lake in Armenia and one of the largest high-altitude lakes in the world. With Lake Van and Lake Urmia, Sevan was one of the three great lakes of the historical Armenian Kingdom, collectively referred to as the Seas of Armenia, and it is the only one within the boundaries of today's Republic of Armenia. Before human intervention dramatically changed this ecosystem, the lake was 95 m deep and covered an area of 1,360 square km (5% of Armenia's entire surface).