It is named after the politician and captain of the Spanish electricity industry José María de Oriol y Urquijo.

The dam regulates much of the flow of the Tagus River, the longest of the Iberian Peninsula.

It was built in 1969 and is the second largest reservoir in Europe.

[3][4] In 2024, a pumped-storage project was approved to use the Alcántara reservoir as the upper reservoir, and Cedillo as the lower, with around 100 m height difference serving two reversible turbines at a combined 440 MW.

[5] The Roman Alcántara Bridge is located 600 m downstream from the dam.