The start and finish are in the car park, which is on the right-hand side of Rue des Frères Robin when coming from Versailles, before the church.
(S/E) Go to the end of the car park (away from the street) and cross the footbridge over the Bièvre. Turn right onto the Sentier Maurice et Alain-Victor Marchand (GR®11) and follow the Bièvre on your right. At the end of the path, climb the steps to reach the embankment of the Etang de la Geneste.
(1) Turn right onto the dyke. At the end of the dyke, take the forest path on the left (follow theGR®11, white and red markings). Follow the Étang de la Geneste on your left. At the end of the pond, ignore a path on the left and continue to a crossroads.
(2) Continue straight ahead, still on a wide path (GR®11).
(3) Take the paved road on the right. Be careful, as there may be traffic.
(4) At the fork, turn left and pass under the D91 (four-lane road). At the roundabout, go straight ahead and descend the path that runs along the eastern bank of the Étang du Val d'Or.
(5) Leave theGR®11temporarily and follow the eastern bank of the pond, then turn left to follow the northern bank.
(6) At the end of the Étang du Val d'Or, climb the steps on the right and take the forest road on the left. This will bring you to a car park.
(7) Take the Épi d'Or forest road, which climbs gently, gradually moving away from the Étang du Moulin à Renard through the Versailles national forest. Continue to the end of the Épi d'Or road, close to the N12 (the sound of traffic on the main road is a good landmark). Continue along this road until you reach a T-junction.
(8) Then turn left, rejoin theGR®11and walk for about 50 metres. Turn left again and descend gently towards the Étang du Moulin à Renard (Route de la Fontaine Blanche).
(9) When you reach the edge of the Étang du Moulin à Renard, turn right onto the path that runs alongside it.
(10) When you reach the end of the pond, turn left twice and walk along the southern bank of the pond. At the end of the pond, leave the car park on your left and continue along the road that runs alongside the fence surrounding the Étang de la Minière.
(11) At the end of the fence, leave the road on your right and the dyke on your left, and descend towards the path that runs along the southern bank of the Val d'Or pond. Follow the southern bank of the pond.
(5) Go back up towards the roundabout and take the road that passes under the D91.
(4) Take the paved road on the right.
(3) Continue straight ahead on Route des Prés. Ignore the perpendicular paths and, after about 1 km, you will reach the Étang de la Geneste. Follow the southern bank of the pond to the retaining dyke. Then turn right and follow Chemin du Cimetière to the village of Buc (ignore a turn-off on the right). Turn left opposite the church, then left again to return to the car park (S/E).