The Keban Dam is a hydroelectric dam on the Euphrates, located in the Elazıg Province of Turkey. The dam was the first and most upstream of several large-scale dams to be built on the Euphrates by Turkey. Although the Keban Dam was not originally constructed as a part of the Southeastern Anatolia Project (GAP), it is now a fully integrated component of the project, which aims to stimulate economic development in Southeastern Turkey. Construction of the dam commenced in 1966 and was completed in 1974. Keban Dam Lake (Turkish: Keban Baraj Gölü), the reservoir created by Keban Dam, has a surface area of 675 square kilometres (261 sq mi) and is reputedly the fourth-largest lake in Turkey after Lake Van, Lake Tuz, and the reservoir created by the Atatürk Dam.
Construction of the Keban Dam was first proposed in 1936 by the newly established Electric Affairs Survey Administration, but not started before 1966. Construction was carried out by the French-Italian consortium SCI-Impreglio and completed in 1974. Estimates of the total construction cost vary between US$85 million and US$300 million. At that time, archaeological rescue missions had also been carried out at important sites that were to be flooded. Flooding of the reservoir started in 1974 and led to the displacement of 25,000 people. During the flooding of the Keban Reservoir, Turkey maintained the discharge of the Euphrates at 450 cubic metres (16,000 cu ft) per second, as agreed with the downstream countries of Syria and Iraq. However, as a result of the fact that Syria was at that time filling the reservoir of its newly constructed Tabqa Dam as well, in 1975 a dispute broke out between Syria and Iraq over the amount of water that flowed into Iraq. This dispute, exacerbated by drought which reduced the amount of available water even further, was solved by mediation of Saudi Arabia. After the initial filling of the lake, geological weaknesses in the bedrock on which the dam was built necessitated a temporary lowering of the lake level in order to carry out extensive reinforcement works. Reportedly, Keban Dam was the world's eighteenth-tallest dam at completion, creating Turkey's largest man-made reservoir and third-largest lake until the filling of the reservoir of the Atatürk Dam.