Lac d'Orient, Water reservoir in Aube, France

Lac d'Orient is a 2,300-hectare artificial reservoir in the Aube, 12 km east of Troyes, held by five earth dikes (Géraudot, Chavaudon, Beaumont, la Morge, Mesnil-Saint-Père) up to 25 m high and 5.7 km long in total. It has no islands but eight peninsulas and about a dozen coves, all in its northern part; the main peninsula is la Petite Italie. Its maximum depth is 18.7 m and varies with the filling level.

After the Seine flooded Paris in 1910, plans for an upstream reservoir met fierce local opposition in the 1930s. Work began on 18 November 1959 without consultation with the Aube residents, and the lake, then called Lac de Lusigny, was inaugurated on 29 March 1966 by equipment minister Edgard Pisani. In 1967 the Aube general council renamed it Lac de la forêt d'Orient.

The lake takes its name from the Forêt d'Orient, whose name comes from the Templars, who owned part of the site in the Middle Ages. The lake was inaugurated on 29 March 1966 as Lac de Lusigny; in 1967 the Aube general council renamed it to promote tourism. Today it is used for swimming and sailing.

The lake is accessible year-round, but water activities concentrate from March through November when conditions are most favorable. Supervised swimming is only available during summer months, while other sports like sailing and kayaking typically start earlier in the season.

The water follows a seasonal rhythm governed by Seine River flood management needs, causing the water level to shift throughout the year. These constant fluctuations create shifting landscapes at the shoreline and shape the plant and animal life.