The Essonne Winter Games in Marcoussis is a winter off-road multisport event in the Essonne department, southwest of Paris. It is organized by CDT91 and Marcoussis Triathlon with support from the town, and it is affiliated with the French Triathlon Federation. The program accommodates varied abilities, featuring a short-format Cross Duathlon, a short-format Bike and Run, and a Family Bike and Run for younger or less experienced participants.
The Cross Duathlon is an individual event: 4 km of running, primarily on forest trails, followed by 15 km of mountain biking over three and a half laps, and a final 2.1 km run. The Bike and Run is a 16 km team race over four laps, where two partners share one bike, remain close, exchange roles during the event, and finish together. The courses are intentionally not technical, making the day suitable for club athletes, casual off-road racers, families, and individuals new to this format.