The route starts at the Pont de la Saine (where there is a car park), near the RD279 road and less than 2 km from Syam.
(S/E) Head straight towards the small hill, following the minor road (south-east) for about 100 m.
(1) Turn left at this junction (towards Chaux-des-Crotenay). Follow this small tarmac road, running close to the River Saine, for just under 1 km.
(2) Shortly after a slight bend, take a path on the right, following the yellow markings. A little further up, continue along the route following the yellow markings: go straight on at the first three junctions, then turn right at the fourth. Further on, you’ll join a forest track.
(3) Turn left at this junction (towards “Chaux-des-Crotenay”), and left again at the next one, following the yellow markings. A little further on, you’ll pass by a hut.
(4) You’ll arrive at a place called La Voie Sacrée. Turn left onto the path (towards “Chaux-des-Crotenay”). At the two junctions you come to, carry on straight ahead. Turn left onto the track, then carry on straight ahead at the place known as La Carrière (elevation 776), ignoring the signposts (particularly the one for “Chaux-des-Crotenay”).
(5) Here, join the D16 on the outskirts of Chaux-des-Crotenay. Continue left for a few metres and head towards the Route des Combes on the left. At a bend, carry straight on along a track that runs parallel to the D16. You will reach a crossroads at the place known as Derrière la Montagne Ronde.
(6) First turn left then right to join the RD16 road – take care. From here, follow the red and whiteGR®® signposting. Less than 300 metres further on, take a path on the right, heading towards the Church of La Chaux, until you reach the hamlet of Les Petits Épinois.
(7) Continue straight on along the path. Further on, you’ll come to a small road; follow it to the right. You’ll reach the Col du Gyps.
(8) At the pass, look out for and take a path on the left (no signposts), which climbs almost straight up a fairly steep slope. Almost at the summit, turn right onto a path leading to the viewpoint (a lovely spot).
(9) Retrace your steps slightly and turn right to join another path leading downhill (follow the yellow markings). Further down, you’ll come to another path at a place called Le Rachet. Turn right, towards the Church of La Chaux (follow the white and redGR®® markings). After a short climb, the path descends until it reaches a small road at a place called La Loye. Carry on straight ahead to the Church of La Chaux.
(10) Walk round the church, turn left and then, a short distance further on, turn right onto the small road to reach Chaux-des-Crotenay. Turn right onto Rue de la Petite Combe and then left onto Route d’Entre-Deux-Monts.
(11) Cross the Grande-Rue, carry on straight ahead along the Route de la Piscine towards Les Prés Grillets and pass the swimming pool.
(12) Turn off onto a path on the right at a place called Le Cornouiller (follow the yellow and redGR®® de Pays markings).
(13): At this junction with the Chemin des Ânes Cornus, carry on straight ahead along the small road. Just under 400 m further on, follow a path to the right, marked with yellow and red signs. At the hamlet known as Les Messageries, take a forest track to the left. A little further on, you’ll join the Route de Cornu.
(14) On the road, turn right. At a bend, ignore a path branching off to the left at the place known as ‘la Grande Cheminée’. About 100 metres further on, take a path leading to the ‘Belvédère les Prés Grillets’ (a lovely viewpoint).
(15) Retrace your steps to the junction at La Grande Cheminée and continue along the path on the right. You’ll reach the entrance to the Grotte de la Grande Cheminée; the exit is visible just a few metres ahead if you look up.
(16) Cross the cave (which is actually more of a hole) using the cables and rungs provided to emerge a little higher up. Great care is required on this section. Carry on to the right, then turn left onto a path that climbs briefly before descending. After turning left, you’ll reach a junction at Sapin Président.
(17) Carry on straight ahead, skirting the Plan d’Eau des Pêchettes (a lovely spot). At the far end of the pond, take a path on the right towards the Pont de la Saine, which then becomes a downhill slope. After a short while, you’ll come to a new section of path (which bypasses an area where water-soaked timber is stored at elevation 534): turn right, following the yellow-and-red markings (an uphill section to the small stream, then turn left, then a little further on, turn left again at a fork). Once you rejoin the path in a clear, open area, continue to the right.
(1) Turn left to return to the starting point, which is very close by (S/E).