Yerres Trail By Night is a night trail race held in Yerres, located in the Essonne region southeast of Paris. Participants can select between 12 km and 22 km distances, both crossing forest trails, with headlamps necessary for visibility after dark. The number of entries is limited to 1,000 runners, making it a local event with a set capacity rather than an unrestricted mass participation race.
The course winds through the Foret de la Grange and concludes at the Yerres Sport Complex. Runners can participate individually or as part of a group with friends, colleagues, or family. The event is designed for a wide audience, not exclusively for seasoned trail runners. Upon finishing, participants receive goodies, a medal, and homemade refreshments. The race also contributes to a charitable cause and promotes handisport, connecting the night run to inclusion and solidarity alongside the athletic challenge.