Lake Annecy is a perialpine lake in Haute-Savoie in France. It is named after the city of Annecy, which marks the start of the Thiou, Lake Annecy's outflow river. It is the third-largest lake in France, after the Lac du Bourget and Lac de Grand-Lieu, if the French part of Lake Geneva, which is shared between Switzerland and France, is excluded. It is a popular tourist d…Lake Annecy is a perialpine lake in Haute-Savoie in France. It is named after the city of Annecy, which marks the start of the Thiou, Lake Annecy's outflow river. It is the third-largest lake in France, after the Lac du Bourget and Lac de Grand-Lieu, if the French part of Lake Geneva, which is shared between Switzerland and France, is excluded. It is a popular tourist destination known for its swimming and water sports.