Trail du Sidobre

The Trail du Sidobre is a 42-kilometer race with 1,600 meters of elevation gain held in Castres, in the Tarn department, at the gateway to the Sidobre, one of the most extraordinary geological sites in France. The Sidobre is a granite plateau unique in Europe, scattered with fantastically shaped granite blocks — rocking stones, boulder chaos formations, rivers of stones — that create a surreal and fascinating landscape. This granite massif, a remnant of ancient magma that crystallized 300 million years ago, extends over approximately 100 km² between 400 and 700 meters altitude and constitutes the largest granite deposit in Europe.

The Trail du Sidobre course takes runners through this open-air geological museum where every turn reveals a new mineral curiosity. Trails wind between granite chaos formations — those titanic stacks of boulders rounded by erosion — and rock rivers, those gigantic stone flows that fill valley floors like petrified torrents. The Peyro Clabado, an enormous 780-ton block balanced on a tiny pedestal, and the Roc de l'Oie (Goose Rock), whose silhouette evokes a giant bird, are among the most famous curiosities that runners can spot from the trails.

With 1,600 meters of elevation gain over 42 kilometers, the Trail du Sidobre is a demanding event that draws its technicality from the omnipresent granite terrain. Trails cross chaos zones where runners must sometimes climb over or navigate around rock blocks, on irregular ground scattered with oak and beech roots. Climbs through the deciduous forest covering the plateau are sustained and sometimes steep, while descents on wet granite and pine needles can prove particularly slippery. The ambient humidity, maintained by the numerous streams that spring up between the rocks, adds to the course's technical difficulty.

Castres, the start town, is a city of art and history whose colorful houses are reflected in the waters of the Agout River. The town houses the Goya Museum, the most important collection of Hispanic art in France after the Louvre, installed in the former episcopal palace whose gardens were designed by Le Nôtre. The industrial history of Castres, marked by textiles and wool processing, has profoundly influenced the region's development. The Sidobre itself remains an active center for granite extraction and processing, and the quarries that dot the landscape bear witness to this centuries-old activity.

The Trail du Sidobre is a geological adventure as much as a sporting one, a race that transports runners into an extraordinary mineral universe. Its 42 kilometers through this granite chaos offer a truly unique trail experience in France. Aid stations showcase Tarn specialties: Lacaune sausage, neighboring Roquefort cheese, spit-roasted cake, Gaillac wines, and plum brandy. For trail runners seeking unusual terrain and landscapes that defy the imagination, the Sidobre is an essential destination where running transforms into an exploration of a 300-million-year-old world of stone.

Trail du Sidobre is a 42 km trail race with 1,600 m of elevation gain, located in Castres, Tarn. The next edition is scheduled for 31 May 2026.

Find all official information on the race website.