Des Marais et des Bosses 2026

Des Marais et des Bosses begins at La Carrière in Saint-Herblain, near Nantes, sending participants on a 10.5 km loop through marshland and a quarry. This mid-November event is for teams, with pairs and fours working together in a progressive relay. Shorter courses for children and juniors are also offered, alongside listed distances of 1.5 km, 5 km, 21 km, and 42 km. The main relay features a unique format: the first runner begins solo, and teammates join sequentially at the start of each new loop, ensuring the entire team finishes together. For the four-person relay, runner one completes 42 km, runner two 31.5 km, runner three 21 km, and runner four 10.5 km. In the two-person version, the distances are 21 km and 10.5 km. Outdoor Club Herblinois organizes the race, which appeals to friends, families, colleagues, beginners, and more experienced runners seeking a shared experience over individual achievement.