Lake Nemrut () is located in the south-western part of the caldera and is now a freshwater lake. Similar to Lake Van, under the influence of volcanic processes it is gradually becoming a saline lake. The lake is fed by hot springs, which is why it is warmer at the bottom than at the surface and does not freeze in winter. The total area is 4.9×2.1 km, the average depth is 140 m, and the maximum depth is 176 m; the altitude of the lake is above the sea level.