From Le Perray to Rambouillet via ponds, ditches and the Drouette river

Departure from Le Perray station (Transilien N line, on the section between Paris-Montparnasse and Rambouillet). To leave the station, regardless of the direction of arrival, take the underground passage and then the "Rue du Petit Paris" exit.

Red and white markings

(S) When you leave the station, turn left and follow the^GR®®1along Chemin du Vieux Moulin, keeping the railway tracks on your left. At the stop sign, continue straight ahead. Ignore a path on the right and walk along the edge of the Étang du Perray pond on your right. Before reaching number 8 on the street, turn right (forest barrier) and follow a path in the middle of a grassy lane. Continue walking along the pond on your right and pass some fitness equipment.

No markings

(1) At the end of the pond, turn right at a right angle and follow the stabilised path on the pond's dyke (let the^GR®®1trail continue further to the left on a path in the middle of a lawn). Pass through a green metal barrier and immediately turn left onto a narrower paved path, keeping a water channel on your right (do not cross the bridge opposite after the barrier). Cross a small road and continue straight ahead with the channel still on your right. Turn right onto the path and then right again at the foot of an oak tree that provides welcome shade.

(2) At the fork, turn left and leave the water channel and an information sign on your right. Head south-southeast on a shaded path, which is none other than the embankment of the Vieille-Église Aqueduct, underground here. Cross the D61 road and continue straight ahead on a path that is wider than the previous one. Cross a perpendicular path and pass through a forest barrier.

Blue and white markings (more visible in the opposite direction)

(3) When the Vieille-Église Aqueduct becomes open to the sky (it is actually a small canal), follow it on your right and continue south-southeast. At the Ferme de la Quoiqueterie, cross the canal on a stone bridge and follow the canal on your left. At the second bridge, cross the canal and follow it again on your right.

Orange + blue markings (actually rare isolated markers)

(4) Where the aqueduct goes underground again (on the left, small car park and map), continue straight ahead (orange marker on the forest barrier). Continue south-southeast along a wide, shaded bridle path. You will come to a more open area and a crossroads of small roads (you will see the canal again on the left).

Yellow markings

(5) At the crossroads, take the third road on the left, Chemin des Forges (sign). After a few metres, turn right (no arrow here), go through a forest barrier and follow the Rigole des Pieds Droits (information sign), on the grassy verge on either the left or right-hand side. When you reach a small road, follow it to the left. At the T-junction, turn right.

Yellow + Orange + Blue and White markings

(6) At the stop sign, turn right and stay on a path parallel to the road on the right-hand side, separated by a parapet. Cross a channel feeding the pond on the right. A few metres further on, before the "Forêt Domaniale de Rambouillet" sign, leave the road and turn right towards the Étang de la Tour. In the undergrowth, walk along the pond on your right, pass a canoe and kayak base and you will come to a car park.

Red and white + blue and white markings

(7) Continue along the pond on your right (markings well beyond the forest barrier) in more open terrain. At the end of the pond (car park, forest house on the left), turn right and follow the dyke framed by large hedges. Enter the forest.

Red and white markings

(8) At the fork that appears immediately, follow the path on the left (ignoring the blue and white markings on the right) and then turn left with the path. After a forest barrier, cross the D906 road (take care) and continue along the path opposite. At a fork, bear left and descend. At the corner of forest plot no. 21-13, ignore the path leading off to the left and continue straight ahead. The path turns right then left; continue south-west through the fern undergrowth.

(9) At a gravel crossroads (cleared plot on the left), turn right (on the IGN map, the purple^GR®®1route is not updated here). After about 200m, walk along a fence on your right. The path descends slightly and curves to the left.

(10) At the bottom, at a crossroads (forest barrier and houses opposite), turn left onto a path through a copse (no signpost but there is a marker a little further on). In relatively dense vegetation, walk along the Drouette river on your right, with a few views of private gardens beyond. Twice, ignore a footbridge on your right (the first made of wooden logs, the second with a metal plate) and continue straight ahead through an undergrowth of ferns.

(11) Cross the D27 road (take care) and continue along the Drouette river on your right. Ignore a small stone bridge on the right, cross a stream and wind your way through the undergrowth. At a three-way junction, turn right. Cross a stream (you may get wet). You will come out onto a small road.

(12) Turn right onto the road and immediately cross a bridge over the Drouette river on your right and the tail end of the Étang d'Or lake on your left. Immediately after the bridge, leave the road and take the path on the left. Walk along the lake on your left for about 750 metres, ignoring the paths on your right. At the north-western tip of the lake (elevation 156), continue north. At a fork, turn left. Cross a stream via a wooden footbridge and turn south-west onto a gravel path.

(13) At the T-junction (signpost), turn right and follow the^GR®®655and^GR®®1towards Rambouillet. Follow a narrow path that winds through the undergrowth. At a T-junction (not shown on the map), turn left and then immediately right.

No markings

(14) At the next junction, turn right (north-east) onto Route des Places (let the^GR®® continue straight ahead). Cross a path and arrive at Carrefour de la Louvière.

Yellow and blue markings

Then turn left towards Rambouillet. After the Maison forestière des Éveuses on the right-hand side, the path gives way to tarmac. Pass under a medium-voltage power line, ignore a street on the right and follow Rue de la Chesnaie.

Red and white markings

(15) At the "give way" sign, pass under the N10 bridge. At the roundabout, continue straight ahead on Rue des Éveuses. At the next roundabout, continue straight ahead on the same street, which becomes a dead end. Continue downhill on this street, which becomes a one-way street. At the bottom, turn left and pass under the railway bridge. Turn right immediately and go up the street to reach Rambouillet station (E).

To return home:
- Transilien - Line N towards Versailles-Chantiers and Paris-Montparnasse or towards Chartres.

Train timetables: consult the Transilien website.

For motorists:
Both stations have large car parks. Compared to the railway tracks, the Le Perray station car park is located on the opposite side of the starting point: take the underground passage.

Hiking boots are required. The paths are well maintained, some are stabilised and, in June 2016, after periods of exceptional rainfall, they were in good condition: this hike should be possible without difficulty in winter (not tested).

No water sources identified along the route. Bars and shops in Rambouillet, including near the station, and in the centre of Le Perray-en-Yvelines.

A 1:25,000 map is required (at least the one accompanying this description).

Variations:
- If, at the end of the route, you wish to shorten the hike, at the Étang d'Or (12), continue straight on the cycle path and rejoin the main route at the car park.
- At the crossroads (14), you can of course continue to follow the^GR®® (signposting is adequate). However, this route is not recommended as it first takes you through a damp and not very clean part of the forest and then along a road parallel to the noisy N10 (whereas at the crossroads (15), noise barriers significantly reduce noise pollution).

Hike completed by the author on 29 June 2016.

- Three ponds: Étang du Perray (1), Étang de la Tour (6) and Étang d'Or (12).
- Vieille-Église aqueduct, from (3) to (4).
- Other channels contributing to the hydraulic network set up during the reign of Louis XIV to supply water to the Palace of Versailles.
- Pleasant walk along the Drouette, at the very beginning of its course, from (10) to (12).