L'Arvor is the Auray-based long trail race within the Ultra Marin Raid Golfe du Morbihan. It starts at 09:00 with a 12-hour time limit. While named for 56 km, race details indicate the course is actually 59.5-59.7 km, with elevation gain between approximately 494 and 600 meters. It is also a UTMB Index 50K qualifying race.
The course is a solo trail run with a rolling-to-hilly profile, not a mountainous one. The low climb-per-kilometer ratio emphasizes pacing over aggressively tackling ascents. Runners should manage the first half conservatively, maintain pace on runnable sections, and plan aid station visits thoughtfully. A recent edition saw 2,059 finishers, indicating this is a popular Ultra Marin event, not a small community race.