The Trail des Légendes de Brocéliande begins at Lac de Trémelin in Iffendic, Ille-et-Vilaine, Brittany. This September trail-running event is based at the lake’s leisure area, offering races from short nature runs to long distances resembling mountain trails. The schedule features La Boucle de Viviane, a 12 km race with approximately 200 m of elevation gain, alongside longer options: 26 km, 42 km, 54 km, and the advertised 100 km Ultra des Légendes with 2,000 m of elevation gain.
The courses traverse the Brocéliande region, incorporating Arthurian-themed names that align with the local forest mythology: Viviane, Excalibur, La Dame du Lac, and the Ultra des Légendes. Excalibur, a 54 km race with 1,300 m of climbing, is available for solo runners or teams, with the relay exchange point at Saint-Péran. The event caters to a broad range of participants rather than exclusively elite athletes. Its 20th anniversary led to the expansion of the series into a larger ultra format, featuring complete course marking and six aid stations for the 100 km race.