Ultra 01 XT - 100 km 2026

Ultra 01 XT is a 100 km trail ultra based in Oyonnax, in the Ain department of eastern France. Runners start at 5:00 AM from Stade Charles Mathon, and the race packs 4,500 meters of climbing into its long day out. The setting is Haut-Bugey, the southern end of the Jura mountains, roughly halfway between Lyon and Geneva. The 100 km race sits inside the wider Ultra 01 series, which offers five event distances. The available recaps point to a race with a small but committed trail community: past stories cover formats from 69 km to 99 km and even a first 100-mile attempt, with one runner describing the event as having “a scent of authenticity.” A few runners have already listed themselves for the series, so this reads more like a hard mountain-ultra gathering than a big-city mass race.