© 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.

A dam good view

Built from 1923 to 1930, the dam took an enormous amount of work. With a height of 45 metres and a length of 206 metres, this monument produces 25 M Kwh of electricity per year. A viewpoint overlooks the dam, offering a wonderful view of the lake.

New life for the foundries

Tucked in a valley, Forges-des-Salles hamlet is one of the oldest metallurgical sites in Brittany. Since activity stopped in 1880, the school, the pay office, the canteen and the joinery shop have been converted to show off their original functions.

Bon-Repos Abbey in the spotlight

Founded in 1184, Bon-Repos Cistercian abbey is still majestic today. Volunteer artisans work to restore the splendour of the impressive vestiges. In summer, a sound and light show spotlights its architecture.

Forges-des-Salles hamlet is one of the oldest metallurgical sites in Brittany

Did you know?

A village in the lake?

Every 10 years since 1951, the lake is dried out, revealing a surprising landscape: the slate workers’ village re-emerges from the depths with its houses, gardens and locks.

Information & bookings

Le lac de Guerlédan

See the website

Official website of tourism in Brittany