| Lac de Longemer | |
| Pushpin Map: | France |
| Location: | Vosges |
| Coords: | 48.0703°N 6.9506°W |
| Type: | glacial |
| Outflow: | Vologne |
| Basin Countries: | France |
| Length: | 2000m (7,000feet) |
| Width: | 500m (1,600feet) |
| Area: | 0.76km2 |
| Max-Depth: | 34m (112feet) |
| Elevation: | 736m (2,415feet) |
Lac de Longemer is a lake near Xonrupt-Longemer, in Vosges, France. At an elevation of 736 m, its surface area is 0.76km2.