| Lac de Grand-Lieu | |
|---|---|
| Location | Saint-Philbert-de-Grand-Lieu, Loire-Atlantique |
| Lake type | Natural |
| Primary inflows | Boulogne, Ognon |
| Primary outflows | Acheneau |
| Catchment area | 700 km² |
| Basin countries | France |
| Surface area | 62.92 km² (Summer: 35Km²) |
| Average depth | 1.6 m |
| Max. depth | 4 m |
| Surface elevation | 5 m |
| Islands | 3 |
Lac de Grand-Lieu is a lake located to the south-west of Nantes, in the Loire-Atlantique, France, and almost entirely in Saint-Philbert-de-Grand-Lieu. At an elevation of 5 m, its surface area is 62.92 km².
The lake is classified as a Local Nature Reserve, and use of boats on the lake are prohibited for all but a small number of licensed professional fishermen.