The lake of Longemer originates after the Würm glaciation, around 80,000 to 10,000 years ago. It stretches over nearly 6,500 ft (2 km) and is one of the largest in the Vosges mountains. The lake results from glacial deepening and the presence of a frontal moraine that bars the valley. The morphology of this valley is due to the Vologne glacier, whose thickness exceeded 656 ft (200 m) and flowed for more than 9,3 mi (15 km) at that time. Already in 3000 BC, a human presence is attested around the lake by the Neolithic tools found on its shores