The Mratinje Dam is a concrete arch dam in the canyon of the Piva River in Montenegro.
The dam was completed in 1975. Its construction resulted in the flooding of the Piva canyon and the creation of Lake Piva, which, with its 12.5 km², is the second largest lake in Montenegro.
The dam is 220 meters (720 ft) high, one of the highest in Europe. The dam is 268 meters (879 ft) long and 4.5 meters (15 ft) thick at the crest, while it is 30 meters (98 ft) long and 36 meters (118 ft) thick at the base. The foundations go as deep as 38 meters (125 ft) into the ground. 820,000 cubic meters (1,070,000 cu yd) of concrete and 5,000 tonnes of steel were built into the dam.
The hydroelectric power station at Mratinje is capable of producing 860 gigawatt-hours per annum. It has three turbines and generators, each with a generation capacity of 120 MW.
The location of the 16th century Piva Monastery was flooded by the lake, so while the dam was built, the monastery was broken into pieces and moved to a higher ground, 3.5 km away. It was reconstructed in the original way.
Dam was used as location for shooting British produced World War II movie Force 10 from Navarone as main tactical target and it was also pictured on a movie poster.