Piton Haüy, Volcanic summit in Réunion Island, France

Piton Haüy is a volcanic summit in Reunion Island reaching approximately 2,407 meters in elevation. The peak comprises two connected volcanic cones that sit within the larger Piton de la Fournaise massif.

Piton Haüy is a nested pair of basaltic lava cones on the western flank of Piton de la Fournaise, in the Plaine des Sables. The larger cone, open to the north in a horseshoe shape toward the Rampe Quatorze, reaches 2,407 m; the smaller regular cone, 2,345 m, sits inside its crater. The name honours René Just Haüy, the French mineralogist; the site was formerly called cratère Hauy.

The name honours René Just Haüy, the French mineralogist who founded crystallography; the peak was formerly called cratère Hauy. The GR R2 long-distance trail, on its Josémont section, crosses the south-western, southern and south-eastern flanks via the col Lacroix, which separates the peak from the Demi-Piton. The forest road to the Pas de Bellecombe, the main trailhead for the Piton de la Fournaise, passes close to the south-eastern flank.

The hike to the summit follows a forest road leading to Pas de Bellecombe and is accessible for those with moderate fitness. Warm clothing is essential as temperatures drop significantly at night and mist often rolls in.

Inside the larger volcanic cone sits a smaller cone reaching approximately 2,345 meters in height. This nested formation reveals how volcanic processes can create intricate structures within structures.