Start at the Château Rouge crossroads at the top of Mittainville.
(S/E) Set off along the path by the sheep shelters, take the path on the left and head down to a fork.
(1) Continue left to the hamlet of Saugis, follow the road straight ahead and cross the hamlet.
(2) At the crossroads, turn left onto Chemin de la Tour Neuve. The road, which climbs slightly, ends in a track. Continue climbing straight ahead. At the top, you are at 163 m; keep going straight ahead.
(3) At the end, turn left and then right shortly afterwards onto the path leading to an air pollution monitoring station.
(4) At the station, turn left immediately afterwards. Continue along the path, which curves slightly to the right.
(5) A little further on, take a path on the left that leads back down.
(6) At the end of this path, turn left onto an uphill path and continue until you reach the apple trees on the right. Walk a few metres.
(7) Turn onto the path on the right which enters the woods and climbs. A little further on, turn left and continue straight on to the top. You’ll come to a gate; go through it and continue on the left along theGRP® des Yvelines path.
(8) Walk past the SPA de la Berthière and continue straight on. Pass a small crossroads, go straight ahead; at the end of this road, the finish line is on the left (S/E)