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© Emmanuel Berthier
Guerlédan Lake and the Nantes‑Brest canal A freshwater sea!
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Guerlédan Lake and the Nantes‑Brest canal

Between Mûr-de-Bretagne and Bon Repos abbey, Guerlédan lake unfolds its woody shores in inland Brittany. This magnificent lake, formed by the construction of a hydro-electric dam, is nestled in the vast Quénécan forest. A paradise for fans of green tourism!

A freshwater sea!

The largest lake in Brittany

Formed by the Blavet, this immense artificial  lake has a surface area of 4 km2, contains 52 million m3 of water and is 12 km long. Created to feed the Guerlédan dam, it has covered a former slate valley since 1930. Its construction involved the disappearance of the locks along the Nantes-Brest canal. Since then, the waterway has been split into two sections. With its tree-lined coves, its walking paths and views, it is one of the most beautiful sites in inland Brittany.

So many activities

The shores, beaches and water sports centres offer excellent departure points for kayaking, sailing, pedalo or water skiing on the lake. Lucky anglers might bring back pike or pike-perch. A trail goes all the way around the lake. It takes a good two days of walking to complete it. A lovely walk, sporty in parts, leads to the shale ridges and the covered alleyways of Landes de Liscuis Another path goes to Gorges de Daoulas, a narrow and wild valley whose slopes are lined with rocky cliffs. In the forest, there are many marked bridleways and mountain bike trails.

The secrets of great energy and the treasure of the steel industry

Built from 1923 to 1930, the lake dam took an enormous amount of work! With a height of 45 metres and a length of 206 metres, this monument standing on the Blavet produces 20 GWh of electricity per year. A roundabout with a viewpoint overlooks the dam, providing a wonderful view of the water. Still close to the lake, tucked in a valley, nestles the hamlet of Forges-des-Salles with its 40 buildings, one of the oldest steel industry sites in Brittany. Since activity stopped in 1880, the school, the pay office, the canteen and the joinery shop have been converted to show their original functions. It’s an amazing visit.

Did you know?

Bon-Repos: and then there was light

Since 1184, the Cistercian abbey of Bon-Repos has lost nothing of its majesty: volunteer craftspeople are restoring the splendour of its impressive remains. In August, a grandiose Sound and Light show spotlights its history and architecture in a magical two-hour show.

Information & bookings

Le lac de Guerlédan


See the website

Official website of tourism in Brittany