Trail de l'agglo is a spring trail race held at Le Billot in Saint-Pierre-en-Auge, Calvados, Normandy. It utilizes the paths around the Billot site, remaining entirely within the commune. The main events offer runners two trail distances, now approximately 22.8 km and 15.3 km, alongside a 10 km Nordic walk, a walking route, and youth races for ages 5 to 15. Local clubs from Livarot, Lisieux, Mezidon, and R.P.V.O. organize the event, with assistance from the Lisieux and Saint-Pierre-en-Auge area authority.
The start and finish are located near the Halle at Le Billot, which also serves as the bib pickup point on race morning. The course consists of two loop options, primarily on trails with minimal asphalt (under 500 m), passing through the Pays de l'Oudon countryside. Previous editions attracted about 260 participants, indicating a community-focused trail event rather than a large urban race. The longer trail is open to juniors and above, the shorter to cadets and above, and the youth races vary from short 480 m runs to 2.48 km.