Lac des Rousses

Lac des Rousses sits right next to the village of Les Rousses, in the Jura department of eastern France, close to the Swiss border and the Vallée de Joux. At 1,075 metres above sea level it is the highest lake in the entire Jura mountain range, and it feeds the Orbe river, which in turn flows into Lake Joux just across the frontier in Switzerland.

How big is the lake and what makes the water so clean?

The lake spreads across roughly 97 hectares and reaches a maximum depth of about 22 metres. It's ringed by extensive high-altitude peat bogs that are ecologically significant enough to be protected, home to rare bog plants found nowhere else nearby. The water quality is remarkably high — clean enough that it supplies drinking water to several surrounding communes.

What can visitors do here in summer?

Between 1 July and 31 August a supervised beach opens on the lakeshore, with grassy areas for picnics, a pétanque pitch and a watersports centre right next to the swimming zone. From there you can rent sailing dinghies, catamarans, kayaks, pedal boats or stand-up paddleboards. A signposted nature trail sets off from the same spot toward the Rocher du Lac, crossing part of the peat bog on a 450-metre wooden boardwalk so walkers don't damage the fragile vegetation underfoot. For food, the Chalet du Lac restaurant serves visitors from Tuesday evening through Sunday lunchtime.

And in winter?

Once temperatures drop enough for the ice to hold weight safely, the lake turns into a natural open-air skating rink — one of the signature winter attractions of the Les Rousses area. It also serves as a starting point for numerous cross-country skiing and snowshoeing trails, since the lake sits within the wider Station des Rousses, one of France's largest Nordic skiing resorts and a regular host of biathlon World Cup events.

Frequently asked questions

Can you swim in Lac des Rousses? Yes — a supervised swimming area operates every summer from 1 July to 31 August, with a beach and watersports rentals nearby.

How deep is the lake and how large is it? It covers about 97 hectares and reaches a maximum depth of around 22 metres.

How high above sea level is it? 1,075 metres — making it the highest lake in the Jura mountains.

Does the lake freeze in winter? Yes, and when the ice is thick enough it becomes a natural outdoor skating rink.

How do you get to the lake? Lac des Rousses lies right at the edge of the village of Les Rousses, a few kilometres from the Swiss border, within the Jura department.