Trail du Circuit de la Sure is a trail-running series held in Voiron, near the Chartreuse area of southeastern France. This June mountain race has a long history; its first edition took place in 1906, and local accounts suggest it may be the oldest trail race in France.
The main Circuit de la Sure course covers 59.1 km with 3,786 meters of elevation gain, presenting a demanding day on steep terrain. The series also offers shorter distances: Les Balcons de la Sure is 32.8 km with 1,603 meters of gain, and the Tour de Vouise is 12.4 km with 694 meters of gain. The event emphasizes its Chartreuse roots, with the Sure name and Voiron start connecting it to the local mountains.