Lac de Lamoura, Mountain lake in Lamoura, France.

Lac de Lamoura is a glacial lake at 1,156 m in the Jura massif, the highest lake in the Jura. It lies at the southern end of the 10 km Combe du Lac, a synclinal trough of Cretaceous rocks and morainic material, below the anticline of the Forêt du Massacre. The lake is fed by the Bief Froid and loses water through two sinkholes on its north-west shore.

The synclinal trough holding the lake was shaped during the Miocene folding of the Jura massif, about 11 million years ago. The lake itself formed during the Würm glaciation, between 115,000 and 10,000 BP, when the retreating Jura glacier left a moraine that dammed the valley floor; impermeable glacial sediments then allowed water to be stored.

As part of the Upper Jura Regional Nature Park, the lake serves as a focal point for environmental education and outdoor recreation, connecting visitors with regional mountain heritage.

A 2 km waymarked path circles the lake on foot. The Combe du Lac is the starting point of the Transjurassienne cross-country ski race, and the lake lies in the ski area of the four villages that includes Lamoura, where cross-country skiing, alpine skiing and snowshoeing are practised.

The lake's waters drain through two underground sinkholes called gouffres, disappearing beneath the surface to reappear in the Flumen valley after traveling through subterranean passages.