Lake Eber (Turkish: Eber Gölü) is a freshwater lake in Afyon Province, Turkey. The lake used to be connected with nearby Lake Akşehir and was named Tessarakonta Martyron, the Forty Martyrs lake, in premodern times.
The lake is between the district centers of Çay, Bolvadin and Sultandağı of Afyon Province. The altitude of the water surface with respect to sea level is 967 metres. The surface area fluctuates and at times it may be exceed 125 square kilometres. In past the maximum recorded depth was 21 metres.
Lake Eber is a part of Akarçay closed basin, a tectonic basin about 7,600 square kilometres. At the conclusion of the last glacier age (Pleistocene) a vast lake was formed in the basin. But after the water level dropped, the lake was fragmentized into two lakes. Lake Eber is at the north west and Lake Akşehir which shares the same history lies at the south east. Presently the distance between the two lakes (nearest points) is about 10 kilometres
