Belt of redoubts and batteries around Fort de Montgilbert

The climb to Fort de Montgilbert is via Montendry, which can be reached from Chamoux-sur-Gelon (73). Before entering Montendry, take the forest/strategic road on the left up to the end of the tarmac section: park at this junction.

(S/E) Climb opposite towards the east on the path that leads through a few hairpin bends to Fort de Montgilbert. Pass the entrance. Continue along the forest road that descends towards a wetland, crossing it via a sort of dyke. Do not follow the path that turns left to descend, but continue straight ahead along a path that climbs up to the main forest road coming from the right, following it uphill for 250 metres.

(1) At the crossroads, take the forest track on the left, which climbs steadily north-eastwards. This is the old strategic road that served the line of batteries on the ridge, staying on its north-western flank.

(2) At the junction of the climb to Ste-Lucie, continue straight ahead on the path, which becomes less steep. It goes around the last hill on the ridge in a wide curve to the right, leaving the paths leading down to Montgilbert and Rocher des Bruyères on the left, to reach the old Foyatiet battery, whose platform overlooks the Arc Valley.

(3) From the summit, return via the uphill path or descend the ridge towards the south-west (footpaths) to rejoin this path a little further down. At a right-hand bend at a pass on the ridge, make a short detour to the left downhill for a view of the Maurienne and Lauzière valleys unobstructed by trees. Back on the path, continue downhill to the junction you passed on the way up.

(2) From this junction, climb up an old strategic road with hairpin bends to the old Ste-Lucie battery and return by the same route to the junction to continue the descent and return to the forest road crossroads.

(1) Follow it uphill to the left until you reach the next junction.

(4) Turn left onto the old strategic road that climbs to the old Tête Lasse battery via hairpin bends, some of which can be cut.

(5) From the platform to the east of the fort, descend via the same route to the previous junction.

(4) Turn left onto the forest road, which levels out. Leave the path that descends to St-Georges-d'Huîtrières on your left and continue south to nearby Roche Brune. This old battery has been restored as a refuge, and its terrace offers unobstructed views.

(6) Continue south on a path that stays on the ridge, which gradually begins to descend. The top of the ridge is initially a wide, wooded crest, then becomes narrower as the terrain becomes steeper.

After a short detour to the west to lose altitude, the ridge becomes more exposed and rocky: the path leaves it momentarily to cross the eastern flank before returning to the ridge. As the slope gradually levels out, join the forest tracks that lead to the Col du Petit Cucheron.

(7) From the geographical pass, join the beautiful Cucheron forest road on the right. Take it to the right, heading due north. It remains more or less level until a bend, then climbs towards the sources of the Gelon.

(8) Here you have two options:
- either continue along the road, but this route is a little tedious,
- or, as indicated on the map, turn left after the bend to follow a contour line across the Gelon.
After the bridge, let the path descend towards Pontet and climb up a forest track on the right, straight up the slope. It veers to the right, the slope becomes gentler and the track becomes a path to cross the Gelon again and climb up to the forest road. Take it to the left to reach the Source du Gelon crossroads.
Be careful here: this is the edge of the Tourbière, a protected natural area.

(9) Take the forest road on the left, heading due west, and continue on the same level until you quickly reach a T-junction, the left branch of which leads to the Plachaux batteries.

(10) Turn left to visit the old Plachaux batteries, the fort's advanced artillery post.

(11) Return to the T-junction by retracing your steps.

(10) Continue straight ahead on the left along the track to return to the car park where you started (S/E).

The entire route is in the forest, on paths and trails, mainly along a ridge, so there are multiple ascents and descents.
There is only one slightly tricky section, where the ridge narrows between Roche Brune and Petit Cucheron.

The Montgilbert fort is not open to visitors (or no longer). However, all the batteries located along the route are accessible and offer a viewpoint (when the forest allows). Approach them with caution, as they are in a very precarious state (there is a real risk of collapse) except for the Ancienne Batterie de Roche Brune, which has been renovated into a refuge.
This defence system was designed by General Serré de Rivières.

(Between 2 and 3) The most unobstructed views allow you to discover (Maurienne, Bauges, Lauzière).
At (6) Roche Brune (Lauzière, Vallée de l'Huile and Chartreuse).
At (9) there is a remarkable peat bog, which is the source of the Gelon.