Bionaz
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redazione
Access
Bionaz can be reached via the[A5] Turin–Aosta motorway, exiting at Aosta Est, from where you continue north along the Valpelline road, which runs up the valley floor through Valpelline and Oyace to the main town and then continues towards the Place Moulin dam; until June 2027, the link between the motorway and the main road is closed for tunnelling works, and the route runs through the city of Aosta. The main railway station is Aosta, on Trenitalia’s (TI) Chivasso–Aosta line; the section between Aosta and Ivrea is closed for electrification works and is served by replacement buses, with a phased reopening scheduled to begin in January 2027. Local public transport is operated by Arriva Italia, with suburban routes connecting Aosta to the municipalities of the Valpelline. The nearest airport with scheduled flights is Turin-Caselle’s “Sandro Pertini” Airport. The valley is one of the coldest in the region: during the winter months, winter tyres or snow chains must be carried in the vehicle, and the section leading to the dam may be closed due to snow.
Introduction
Bionaz is a municipality in the Aosta Valley, situated at the head of the Valpelline, north-east of Aosta; it is one of the largest in the region in terms of area, yet has one of the smallest populations. The main town, Plan de Veyne, lies in the Buthier valley at 1,600 metres, whilst the municipality’s territory rises to the ridges marking the borders with Valais and Valtournenche, at over 4,100 metres. The municipality borders Ollomont, Oyace, Nus, Torgnon and Valtournenche and, across the border, Bagnes, Evolène and Zermatt. Its history is linked to the two mountain passes connecting it to Switzerland: the Crête Sèche Pass and the Col Collon.
Description
The area comprises the upper Buthier Valley, stretching from the valley floor at the main town up to the border glaciers, and the side valleys that climb towards the ridges: the Montagnayes valley, the Bionaz valley and the Prarayer basin, beyond the artificial lake. The settlement is scattered across some thirty villages, including Plan de Veyne, Chentre, Dzovennoz, Lexert, La Ferrère, Les Places and Prarayer. The construction of the Place Moulin dam in the second half of the 20th century altered thelayout of the valley: the dam is 155 metres high and 680 metres long, and the reservoir holds up to 110 million cubic metres of water, submerging the pastures where the valley’s first hotel once stood.
The two passes were already frequented in pre-Roman times by the Salassi and later by the Romans, but they gained greater importance from the 14th century onwards, when the House of Savoy gradually lost its possessions in the Valais and Bionaz became a border municipality. This led to a trade in contraband salt, tobacco and livestock, which was combated by border guards stationed in the area until 1972. Since the 19th century, the municipality has been a destination for mountaineers: to meet the demand, a small hotel was built in Prarayer, which now lies beneath the waters of the lake. The parish church is dedicated to Saint Margaret of Antioch.
The economy is based on livestock farming and dairy production, supplemented by summer tourism. The municipality is one of the most sparsely populated in the region and has, in recent years, geared its services towards mountain tourism: Lake Lexert, at the bottom of the valley, is equipped for swimming and recreational fishing. Bionaz is part of the Unité des Communes valdôtaines Grand-Combin.
The Montagnayes valley, which opens out just before the dam, is a regional nature reserve and was previously a wildlife sanctuary: it is home to the chamois (Rupicapra rupicapra), the ibex (Capra ibex), red deer (Cervus elaphus) and the roe deer (Capreolus capreolus), along with the hare (Lepus timidus) and the marmot (Marmota marmota), predators such as the fox (Vulpes vulpes), the badger, the marten and the stone marten, and birds of prey such as thegolden eagle (Aquila chrysaetos) and the pygmy owl. In the valley floor, the common toad has a breeding site at Lake Lexert; the buzzard (Buteo buteo) frequents the wooded area right up to the upper limit.
The network of footpaths leads up to the high-altitude refuges at the head of the valley, including those at Prarayer, Crête Sèche, Nacamuli and Aosta, and to the bivouacs in the side valleys. From the Place Moulin dam, routes lead to the lakes of the upper Valpelline and to Lake Livournea, whilst the border passes remain links to the Valais.
Information
General information
Area: 142.09 km²
Altitude of the county town: 1,606 m
Highest point: 4,171 m – Dent d'Hérens
Population: 212 (as at 1 January 2026)
Name in dialect: Biona
Name of inhabitants: bionassin
Patron saint: Saint Margaret of Antioch, celebrated on 20 July
Neighbouring municipalities: Val de Bagnes (Switzerland) – Evolène (Switzerland) – Nus – Ollomont – Oyace – Torgnon – Valtournenche – Zermatt (Switzerland)
Region: Aosta Valley
Country: Italy
Official website: comune.bionaz.ao.it