Bivouac Rosaire-Clermont, from Lignan
Edited by:
Massimo Martini
Updated at: 17/02/2026
Access
Road Navigation
At the motorway junction of Nus proceed in a north-easterly direction for 220m (0.22km). At the roundabout take the first exit and take the Strada Regionale di Fénis, continuing for 600m (0.82km). At the next roundabout take the third exit and, after 97m (0.92km), turn onto the Valle d'Aosta road in the direction of Aosta. Continue on for 900m (1.82km) until you see the entrance to the Saint-Barthélemy Valley on the right.
Turn right onto Via Champagne and after 71m (1.89km) turn right again onto Via Aosta/. After 160m (2.05km) turn left and follow the signs for Saint-Barthélemy, continuing on the regional road . Go up the for 15.7km (17.75km), passing the villages of Petit-Fénis and Blavy and continuing in the direction of Lignan. At a fork in the road, turn left following the signs for Lignan and continue for 190m (17.94km). Turn right and, after 30m (17.97km), you will reach the square in Lignan, the end of the road navigation.
Description of the car park
In Lignan there is a free car park 🅿️ located near the parish church and the Aosta Valley Astronomical Observatory. The car park is the starting point of the itinerary. If there are no more spaces, turn back about 100m where, on the left-hand side of the road, there is a further free car park 🅿️. Near the village there is a fountain 💧 useful for water supply.
Access by public transport
The village of Lignan is served by regular buses operated by Arriva Valle d'Aosta with connections from Nus. Consult the updated timetables at the following official link: https://aosta.arriva.it
The frequency of services may be reduced on public holidays and during the winter period; always check the timetables before departure.
Distance and travel time
🕒Travel time: 27 minutes
📏 Distance: 18 km
GPS navigation
📍 How to get there with Google Maps
📍 How to get there with Apple Maps
Important note
The directions provided were verified on the date the route was surveyed. Before departure, it is advisable to check for any changes to the route. For up-to-date and detailed directions, we recommend the use of Google Maps or Apple Maps.
.Introduction
Return route starting from Lignan, in the Saint-Barthélemy Valley, and arriving at the Rosaire-Clermont Bivouac (2,692m), located near Col Vessona. The route initially follows the 'Path of the Planets', which leads to the Astronomical Observatory of the Clément Fillietroz Foundation, and then continues along farm tracks, alpine pastures and less marked sections of path in the Chaleby valley. After passing the Champanement alpine pasture, you reach the Alta Via no. 1 and, with a last stretch in an open environment, you arrive at the bivouac, located next to a small lake in a panoramic position.
The hike has a significant difference in altitude and development, with medium-long walking times and some stretches where the track may not be very clear, requiring good orientation skills, particularly on the grassy slopes of Plan Piscina. The environment traversed varies from the initial meadows and larch woods to the high altitude pastures and wide grassy saddles near the pass, offering wide views of the surrounding peaks, including Becca d'Aveille, Grand Pays and Mont Faroma.
The recommended period coincides with the summer season, if there is no snow on the upper sections; in the event of fog or poor visibility, orientation may be more complex. Overall, the itinerary is distinguished by the breadth of the spaces and the progressive immersion in an open and silent mountain environment, culminating in the basin that hosts the bivouac.
Description
0h00' 0.00km Follow the signs to the Astronomical Observatory and take a paved road that climbs the meadows in a northerly direction. This section is known as the "Path of the Planets", as a series of explanatory panels, dedicated to the planets and positioned at distances proportional to their actual distance from the Sun, accompany visitors along the access path to the facility. Pass the signpost indicating all the paths from Lignan and, after a few minutes' climb, reach the entrance to the "Clément Fillietroz Foundation" Astronomical Observatory and a crossroads with a signpost.
0h05' 0.32km Turn left and follow the signs for the Rosaire-Clermont Bivouac, signposted at 3h40'. Follow the grassy farm track bordering the Ru de Saint-Barthélemy on a slight slope; a little further on, leave a hamlet on the right, then turn right. Before the hiker, the Becca d'Aveille, the Grand Pays and the imposing southern face of Mont Faroma stand out on the horizon. The little road continues slightly uphill, skirting the ruins of Méant and Pléoles, before reaching the spillway where the waters of the Ru de Saint-Barthélemy are captured. A little further on, cross the Chaleby stream on a ford bridge and turn left, taking the orographic left of the valley. Continue on the road in a southerly direction, crossing an initial strip of larch forest, until reaching the dirt track leading to Brevaz. Turn right and continue on the dirt track until the next fork.
1h15' 3.50km Disregard the track to the left and continue straight on uphill along the orographic right of the Chaleby valley. At a hairpin bend, leave the dirt road and pay attention to the marker on a small rock, indicating the path to the left. Take the path, which in places is completely lost; some yellow arrows indicate the direction to follow (North-North-East). After passing a hump, the arrows also disappear: so keep heading north, climbing up the meadows until you reach the dirt track just before the Champanement pasture (2,327m).
2h30' 6.03km Immediately after the huts, at a water reservoir, an arrow indicates to turn right along a path that leads to intercept the Alta Via 1. There are several ascent possibilities. Take the first visible path on the left and climb up Plan Piscina through meadows without an obvious track, orienting yourself with the help of a few cairns, until you reach the Alta Via path at an altitude of 2.562m.
3h05' 8.51km Turn left and follow the Alta Via, heading towards the wide Col Vessona saddle, until you reach a fork. Turn right here and descend along a short path to the Rosaire-Clermont bivouac (2,692m), located near a charming little lake. 3h40' 7.08km .
The descent follows the same route as the ascent: from the Rosaire-Clermont bivouac, climb briefly up along the Alta Via 1 trail, following it as far as Plan Piscina; then descend again to the Champanement cottages and return along the trail and the dirt track of the Chaleby valley to Lignan (1.636m) 2h20' 8.51km .
.Points of interest
- Nus
- Lignan
- Astronomical Observatory "Clement Fillietroz Foundation"
- Champanement
- Bivacco Rosaire-Clermont