La Thomeryonne is a 10 km trail race held in Thomery, located in the south of Seine-et-Marne. A significant portion of the race takes place within the Fontainebleau forest. It is open to 350 participants, welcoming both experienced trail runners and amateurs, and is suitable for men and women aged 16 and over. The course is not a simple flat run; it is characterized as technical and challenging, featuring elevation changes and varied underfoot conditions.
Runners will navigate through forest trails, paths, and sections of road, including a full kilometer of paved surface, while also passing by significant landmarks within the commune. Previous participants highlight the diverse terrain and the climbing sections as key elements that distinguish the race locally. The event also incorporates a social aspect: 2 euros from each paid entry are donated to Solidarites Nouvelles face au Chomage, and individuals seeking employment can register without charge.