From Le Perray-en-Yvelines to Rambouillet through the forest

(S) Leave Le Perray-en-Yvelines station and take Rue de la Gare opposite, following the red and white markings of the GR®1C. Go straight across the crossroads and continue along Rue de la Breloque. Continue left along Petite Rue Verte until you reach the crossroads with traffic lights at Croix Barbé.

(1) Cross at the pedestrian crossing, continue straight ahead on the same street, pass under the four-lane road (RN10), and continue straight ahead on Grande Rue Verte. Walk along the cemetery on your right, enter the forest, and you will soon reach the junction with Route de la Croix Saint-Jacques.

(2) Continue straight ahead and join Route Sommaire.

(3) Turn left, and after about 200 metres, turn right. Follow the winding path that leads to the Étang de Coupe-Gorge.

(4) Take the track on the right to go around the pond, which is empty even in winter.

(5) Leave the pond on the left, staying on the GR®1C. Join the cycle path and make the first turn right then left to continue the route via the Route des Tailles d'Épernon. Pass the first crossroads and continue to the next one (Chemin de Poigny au Perray).

(6) Turn left, pass the Carrefour de la Cerisaie, and join the D939.

(7) Cross it carefully, follow the road to the left for 100 metres, then turn right, continuing to follow the GR®1C markings. Then turn right to follow the Route Blanche and arrive at the Carrefour Sédillot.

(8) Turn left onto Route des Longues Mares, pass the crossroads of the same name, and arrive at Carrefour de Poigny. Take the forest road on the right.

(9) Leave the forest and head towards Poigny-la-Forêt via Route du Vieux Château, then Route de l'École. You will reach a triangular square called Place Maurice Hude.

(10) Head straight ahead and slightly to the right to go around it. Pass La Guesle, take the road on the left, then the path on the right at No. 15B. Cross Route des Graviers, take the path opposite, which goes further into the woods before leading to Carrefour du Roi de Rome, where it joins the GR®1.

(11) Turn left towards Rambouillet. Pass the Carrefour de la Croix Jouanne and follow the GR®1 markings, which invite you to turn left to join the D107 at the end of the Étang d'Angennes. Continue to the left, cross the bridge and arrive at the water treatment plant.

(12) Leave the road and turn right to discover the Rochers d'Angennes, a "mini Fontainebleau". Then leave the GR® temporarily, taking a short detour to the right to walk along the edge of the lake, rejoin the GR® and continue the route to the right to arrive at the Carrefour des Rabières. Take the forest road on the left and reach the Carrefour des Grosses Haies.

(13) Leave the GR®1 and turn left. Leave the antenna on your left and join a tarmac road at a place called La Grosse Haie.

(14) Take it on the right: this is the least pleasant part of the hike, but it is not very long. Continue straight ahead until you reach Carrefour des Chartreux.

(15) Continue straight ahead on the road until you approach a right-hand bend.

(16) Turn left to pass a forest house and a wall. Follow this wall, which marks the boundary of a private estate and requires a long detour.

(17) Cross Route de Poigny and continue straight ahead until you reach the junction with the D936.

(18) Turn right and walk carefully along the road for about 400 metres.

(19) Take the path on the left, before the Porte de Houdan, to avoid the road. Turn left again onto Route Crève Cœur.

(20) Turn right onto the first path (Route de Maillard) parallel to the D936. Cross several crossroads, come out onto Route de Rambouillet (PR® junction, yellow markings), and continue to the right until you reach the junction with Route de Coupe-Gorge. Turn right and rejoin the D936.

(21) Cross over and enter Rambouillet Park. Pass Rond de la Chasseuse and continue straight ahead.

(22) Take the road on the right, following the PR®; go straight ahead at the junction with Route de la Ferme and rejoin the GR®1.

(23) Turn left onto a path to walk alongside the castle's ponds.

(24) Take a path, again on the left, at a 90° angle, to finish walking alongside them. Go around the Rondeau, and head to the right to exit the park and reach the roundabout.

(25) Go around the roundabout on the right, take Rue Chasles, and continue straight ahead to reach the south car park of Rambouillet station. All that remains is to reach the station (E).

Access from Paris by public transport: you can take the TER (faster) with a Navigo pass from Rambouillet.

(13) If you are tired, after Les Rochers d'Angennes, you can continue on the GR®1 to reach Gazeran. This will save you 4 or 5 km.

Note that there are two short stretches on the road that are not very pleasant but fairly quick: no more than 500 to 600 m in total.