Pierre Allain, born January 7, 1904 in Mirebeau (Vienne) and died December 19, 2000 in Saint-Martin-d'Uriage (Isère), was a French mountaineer and climber. He is also an inventor of technical innovations in mountaineering. According to the minister and mountaineer Pierre Mazeaud, Pierre Allain is the “first French mountaineer”.

Pierre Allain, raised in Paris, discovered mountaineering on vacation in the Alps in the 1920s. In 1930, his friend Robert Latour introduced him to climbing in the forests of Fontainebleau and Chamarande. He therefore joined the Bleau Group (including Marcel Ichac, Pierre Chevalier, Jean Deudon, Raymond Gaché, Alain Le Ray, Jacques Boell, etc.). In 1930, he made his first real mountaineering season in the Alps with Robert Latour. Like the other Parisian mountaineers, he therefore spent the summer season in the Alps and climbed the rest of the year in Fontainebleau.

Among his notable ascents: In 1933: first of the south-west ridge of the Aiguille du Fou with Robert Latour. In 1934: first on the south-west ridge of Pic Sans Nom with Jean Vernet and Jean Charignon and first on the south face of La Meije to Glacier Carré with Jean Vernet and Jean Leininger. In 1935: first ascent of the north face of the Petit Dru with Raymond Leininger, then opening of a "directissime" on the south face of La Meije from the Glacier Carré, with Raymond Leininger (end of the route opened in 1934). Also first on the east face of the Dent du Caïman with Raymond Leininger. In 1936: first French expedition to the Himalayas (Karakoram) with his comrades Jean Leininger, Marcel Ichac, Jean Charignon, etc. The assault rope led by Pierre Allain reached 6,850 meters then gave up due to the monsoon storm, 3 weeks ahead of schedule. In 1937: first on the east ridge of the Dent du Crocodile with the brothers Jean Leininger and Raymond Leininger and first on the north-east ridge of the Grands Charmoz with Yves Feutren. In 1938: premiere (without throwing a rope) of Le Doigt de l’Etala at the Petits Charmoz with Jean Leininger. Attempt at the Walker spur at the Grandes Jorasses with Raymond Leininger who will be defeated a few days later by the Italians led by Riccardo Cassin. In 1944 he participated in the Liberation of the Arve Valley from German occupation. Other alpine exploits followed: In 1945: crossing of the Aiguilles de Chamonix from Plan to Grands Charmoz with Guy Poulet. 1946: third ascent of the Walker spur (of the Grandes Jorasses) with Guy Poulet, René Ferlet and Jacques Poincenot. 1947: premiere of the south-west face of the Cardinal with F. Aubert, Auguste Fix and J. Rousseau. Premiere of the west face of Blaitière with Auguste Fix. In 1950: First of the northwest ridge of the Grands Charmoz with Marcel Schatz. A modest man, above all a craftsman, Pierre Allain refuses the presidency of the High Mountain Group (GHM), which brings together the elite of French and even world mountaineering. 1963: Pierre Allain leaves Paris to settle permanently in the Alps, in Uriage in the Dauphiné. He devotes his time to his workshop which manufactures light carabiners, caving ladders, etc. 1984: at the age of 80, he climbs the Boell route at La Dibona, with his son Paul.