A 100 mile mountain ultramarathon in Eryri (Snowdonia) traversing remote upland terrain including summits, ridgelines and deep valleys. The route combines established mountain paths with rough ground, steep climbs and technical descents typical of the region. Elevation gain is substantial and spread across multiple major ascents rather than a single climb. Underfoot conditions vary from rocky trail to uneven mountain terrain, with exposure on higher ground. Navigation requirements, checkpoints and aid station provision are defined by the organiser’s official race information.