La Mervilleuse begins at Stade Charles Rattez in Merville, a town in the Nord department of Hauts-de-France, and takes place in March. It features road races of 5 km and 10 km, a 21 km nature trail, children’s races of 400 m and 1 km, and walking options for those who prefer to follow the route without competing.
The 21 km trail is mostly flat, with approximately 10 m of elevation gain, focusing on distance rather than challenging climbs. Marked walking routes are available, including a 10 km course mirroring the 10 km race and a 21 km course matching the trail. Children compete within the stadium grounds, music is provided along the routes, and the finish area offers refreshments and a food vendor.