Berjatrail is a late-autumn trail event in Bourgoin-Jallieu, Isère. Runners can choose nature courses of about 9 km, 16 km, or 24 to 25 km, and the event also includes Nordic walking. It is organized by CSBJ Athlétisme, and the starts are set late enough for the longer routes to run into darkness.
The routes mix town paths with forest tracks, undergrowth, a pond, and the small climbs typical of Nord-Isère, with up to about 480 m of elevation gain on the longest course. A headlamp is part of the experience, giving the race a night-trail feel without extreme distances. Many runners use it as preparation for SaintéLyon, testing pacing, kit, and night running conditions. The finish area usually includes a race village with hot food, entertainment, and an ecological approach from the organizers.