The Maulde is the most important source of water for the lake, and the lac de Lavaud-Gelade, a 285-hectare (700-acre) reservoir to the east, is able to feed it via an underground canal.

The lac de Vassivière is surrounded by more than 7,600 hectares (19,000 acres) of land of ecological or natural interest (ZNIEFF: French: Zone naturelle d'intérêt écologique, faunistique et floristique), level 1, grouped in 15 distinct areas.

These present the full range of landscapes characteristic of the Plateau de Millevaches: peat bog, wetland, heath and forest.

The bogs, in particular, are unique and fragile small ecosystems, composed of many strata of plant material, and forming a carbon sink.

It is surrounded by many different communes, including: As the lac de Vassivière is entirely inside the Millevaches Regional Natural Park, large parts of its shoreline are protected from excessive development, and form an important haven for wildlife, and wild flowers in particular.

It is dominated by a château and features a number of exhibition and performance spaces, a landscape sculpture park and small menagerie.