Thur Trail begins in Mitzach, a village in the Haut-Rhin department of Grand Est, situated at approximately 420 meters elevation. Held in April and organized by Ski Club Ranspach, it is a mountain trail race on the Rossberg massif within the Ballons des Vosges regional nature park. The event offers runners multiple distances, including the approximately 10 km Le Sentier M race with 360 meters of elevation gain, and Les 3 Vallons, a 53 km route covering about 2600 meters of ascent. Past editions have also featured Le Rossberg and La Mitzachoise, catering to both newcomers to forest trails and those seeking a long UTMB Index or qualifying race.
The courses start at the Place des Fêtes in Mitzach, proceeding along a country road for about 500 meters before transitioning to mountain paths and forest trails. All races follow the initial 3 km together before diverging, with the Sentier M looping around the Mitzach valley. The event attracts trail runners, spectators, volunteers, and local partners, with the Rossberg distance typically seeing the most participants among the mid-range options. A separate schools race provides children from CP to CM2 in the Haute Thur valley with a 1000-meter run, un wakted and unranked, offering participation rewards for all and a trophy for the school with the highest number of finishers.