Lake Ilı (, hot lake) was split from Lake Nemrut by an ancient lava flow. Ilı is located closer to the fault than Lake Nemrut; therefore it has a larger inflow of hot springs and a higher temperature. In the summer, it sometimes reaches 60 °C, and an average is 6-8 °C warmer than expected for a lake of its altitude. Nevertheless, it partly freezes in winter because of the small size and depth.