Trails de la Brie des Morin begins in Saint-Cyr-sur-Morin, Seine-et-Marne, east of Paris, leading runners into the Vallée des deux Morin. Held annually in spring, it is a trail-running series offering several distances: recent options have included 10.1 km, 25.4 km, 42.9 km, and approximately 60 km, with the longest trail featuring about 1,300 meters of elevation gain.
The courses traverse forest paths, narrow single tracks, fields, villages of the Brie region, and sections of local historical sites. The 10.1 km event is named La Course des Têtards, and its hiking counterpart is La Rando des Têtards. The 25.4 km race is known as the Trail du Tacot Briard. The organizers, JSFG of La Ferté-Gaucher, also host the Trail Briard by night, where participants navigate Brie's trails using headlamps in a relaxed group setting.