The Ullíbarri-Gamboa Reservoir (Basque: Uribarri Ganboako urtegia, Spanish: Embalse de Ullíbarri-Gamboa) is located in Álava, Basque Country, Spain. With a total capacity of 147.2 hm3, it is the largest reservoir in the Basque Country. Together with the nearby Urrunaga Reservoir , it provides water to the nearby city of Vitoria-Gasteiz and to Bilbao and its metropolitan area. The whole reservoir has been designated as a Natura 2000 site, and the southeastern end of the reservoir is also protected as a Ramsar wetland. It is also a popular leisure area, particularly for hiking and bathing.
