Route des 4 Châteaux de Chevreuse is a mid-November trail race starting in Chevreuse, in the Vallée de Chevreuse in Yvelines, about 30 minutes from Paris. The main race is a single-loop trail of about 17 to 18 km, with roughly 250 m of climbing, making it short enough for many club runners but still offering substantial off-road running.
The curious detail is in the name: although it is the Route des 4 Châteaux, the course passes at least five châteaux. Runners encounter a mix of castles, forest, and valley paths, and the event attracts a local Île-de-France crowd rather than feeling like a large-city road race. It has been held long enough to reach more than twenty editions, and French race listings categorize it as a small-format Trail XXS event.