OCS Millevaches en Limousin has no clock, no ranking, and no sprint finish; the objective is to complete a challenging self-supported route. This is a weekend ultradistance bikepacking event in Haute-Vienne, Nouvelle-Aquitaine, and it is part of the Outdoor Cycling Series. Participants select either a 150 km or 350 km course, choosing between road or gravel, and may ride continuously or rest as needed.
The route crosses the Regional Natural Park of Millevaches in Limousin, an extensive upland region covering Creuse, Corrèze, and Haute-Vienne. The event begins in Saint-Léonard-de-Noblat, the hometown of the renowned French cyclist Raymond Poulidor. The rider limit is set at 100 participants. As it is also a stage of the Tour de France des Parcs Naturels Régionaux, the format resembles a small, self-sufficient cycling journey rather than a conventional competition.