Orava is a reservoir in northernmost Slovakia, forming the largest lake in Slovakia (35.2 km²). It was created by the construction of a dam between 1941 and 1953 on the former two sources of the Orava river. Several former villages had to be inundated for this purpose. Probably the best known of them was Slanica, the birthplace of the Slovak intellectual and cleric Anton Bernolák (Antonius Bernolacius). Today, the reservoir is protected by the Horná Orava Protected Landscape Area.
The average depth of the reservoir is 15 meters. In the northeastern extension of the reservoir is Vtáčí ostrov (Birds' Island), a government ornithological reservation. Species like herons, great cormorants, spoonbills and others inhabit the reservation, which is one of important bird areas of Europe. The wetlands around the reservoir are also regarded as one of the most important in Europe. The protection of the forests skirting the Orava Reservoir have helped check erosion.