Saint-Pierre, Réunion · Trail
Official site ↗Diagonale des Fous
The Madmen's Diagonal: about 180 km and 10,000 meters of climbing across Réunion Island, from Saint-Pierre on the south coast to Saint-Denis in the north, one of the hardest and most followed 100-milers in the world.
Distances
- Distance
- 180 km (112 mi)
- Vert gain
- 10,200 m (33,500 ft)
New route via the Salazie cirque and Hell-Bourg; the longest Diagonale yet · WSER 2027 qualifier (sub-50:00)
| Distance | Vert gain | Notes |
|---|---|---|
| 180 km (112 mi) | 10,200 m (33,500 ft) | New route via the Salazie cirque and Hell-Bourg; the longest Diagonale yet · WSER 2027 qualifier (sub-50:00) |
About
La Diagonale des Fous, the Madmen's Diagonal, crosses Réunion Island corner to corner: a Thursday night start at Ravine Blanche in Saint-Pierre, a climb onto the flanks of the Piton de la Fournaise volcano, days and nights through the island's cirques and Réunion National Park's UNESCO-listed terrain, and a finish at the La Redoute stadium in Saint-Denis, the capital on the north coast. The terrain is famously technical, the climbing totals around 10,000 meters, and the whole island turns out to line the trail; it is widely considered one of the hardest 100-mile races anywhere.
It is the longest race of the Grand Raid de La Réunion festival, which also carries the Trail de Bourbon, the Mascareignes, the Métis Trail, and the Zembrocal relay across the same October weekend. From 2026 the course routes through the Salazie cirque and Hell-Bourg instead of Cilaos, making it the longest Diagonale yet at about 180 km.
Course
South to north across the island from Ravine Blanche in Saint-Pierre to the La Redoute stadium in Saint-Denis. The 2026 route runs about 180 km with 10,200 meters of positive gain, passing Notre-Dame-de-la-Paix, the Plaine-des-Cafres, Cap Anglais, Bélouve, and Hell-Bourg in the Salazie cirque, then Mafate (Grand Place, Roche Plate) and the Maïdo before the long drop to the coast at La Possession and the Chemin des Anglais into Saint-Denis.
How to register
Non-residents pre-register on the official site by early March for a lottery drawn in mid-March; the Diagonale exceeds its quota every year. Validation requires having finished two qualifying races worth at least 85 points each (1 km = 1 point, 100 m of climbing = 1 point). Partner agencies also sell bib-plus-travel packages outside the lottery.