Icio'trail starts at 9 AM beside the lake in Usson-en-Forez, a village in the Loire department of France. It is a nature trail race held around mid-September, with four distance options: 10 km, 17 km, 29 km, and 42 km. The format is simple and unusual: everyone begins together on the same first loop, then runners decide at the lake whether to finish or head back out for another loop.
The opening yellow loop is 10 km with 200 m of climbing. Anyone continuing adds the red 7 km loop for 17 km total, then the green 12 km loop for 29 km total, and finally the blue 13 km loop for the full 42 km, which reaches 950 m of elevation gain. Usson Sport Nature, the local nature running club, organizes the race, and the 42 km option is listed as the most popular distance.