The walk starts in front of the town hall in Tersanne, a small village in the north of the Drôme, a few kilometres south of Hauterives. Start from the car park between the town hall and the primary school in Tersanne.
(S/E) Leave the car park via the one-way street. It runs alongside the north gable of the school. Turn right to pass in front of a fountain topped with a rooster. Head towards Hauterives. At the next fork, immediately turn left. Go straight ahead at the crossroads.
(1) At the sign indicating the village exit, go up to the left (Chemin des Marnières). This leads to a small road which you take on the left. When this turns left, go straight ahead.
(2) When you see a cross on your right (white plaque with a message addressed to "Jeunes Filles"), take the gravel path on the left. It leads to a small road with a large gate in front of you. Turn right, then take the first small tarmac road that goes up on your left (Chemin des Simians). At the hamlet of Les Simians, continue straight ahead on a gravel road.
(3) You will come to a stud farm. Turn onto the path that branches off to the right after a shed. This path leads to the D538, which you cross (be careful, traffic travels fast). There are two gravel tracks; take the one on the left (yellow markings), which is less travelled, along the departmental road (the other leads to a private residence). You will pass an antenna and a water tank.
(4) You will see a sign for "Réservoir alt. 485m". Turn right towards Saint-Pierre. You will pass a metal cross. (Take the time to admire the tiny Christ figure in the centre and enjoy the view of the Vercors). Pass a path on your right, then another on your left.
(5) When you reach a T-junction, you will see wooden signs and, on the left, a sign for "St Pierre - alt. 489m". Take the road on the left towards La Tironnerie. At the next fork, continue on the left again. Follow this road for a long time.
(6) At a place called "Ambouchet", you will see a transformer on your right. Continue straight ahead. At the next fork (signposted "Route du Levant"), turn left. The road makes a sharp left turn and descends before climbing again.
(7) You will cross the D538 again. Go up the hill opposite. At the crossroads immediately after, go straight ahead. The small road turns left.
(8) You come out onto a small road, which you take on the right, then immediately descend onto a grassy path on the left (yellow markings). This wide path narrows to become a narrow trail (watch out for brambles).
(9) You will come out at the back of a house, then onto a small road which you take on the right despite the yellow cross.
(10) Pass near the Vermeille spring. Continue to the village and your starting point (S/E).

