Follow the Yvette from Essarts-le-Roi to Saint-Rémy-lès-Chevreuse

Starting point and access: Essarts-le-Roi railway station.
- Transilien – Line N, on the section between Paris-Montparnasse and Rambouillet.
Take the Rue de la Cité exit on the side of platform 1, which is the platform for trains travelling from Paris to Rambouillet (if arriving from the opposite direction, use the underpass).

No signposting

(S) On leaving the station, follow Avenue de la Gare straight ahead – slightly to the left – towards the town centre. Walk past the post office on your right, cross Place du 8 mai 1945 and walk past the market. At the corner by the fire station, turn right onto Rue du 11 Novembre.

At the fork in the road, turn left, staying on Rue du 11 Novembre, with the war memorial on your right. Walk past the town hall and continue along Rue de la Bourbonnerie. At the junction, turn left, staying on Rue de la Bourbonnerie. At the next junction, cross the D202 and continue straight ahead along Rue des Gandines. Walk past the cemetery on your right, then ignore two small streets on your left.

(1) At the fork in the road, turn left onto Chemin de Vaujoyeuse (a dead end). Walk alongside the wall of a property on your right. The tarmac gives way to a path which, after a shaded stretch, leads between two fields. Enter the woods again. Pass under a power line (farmhouse on the left) and continue along a fence on the left-hand side. At a fork in the road, turn left and walk alongside a meadow on your left.

(2) At the corner of the meadow (boundary stone), turn left onto a narrow path that runs alongside the meadow. Further on, the path moves away from the meadow and winds through dense vegetation. Cross the wet sections using wooden planks placed at intervals and reach the source of the Yvette (statuette).

(3) Retrace your steps back to the boundary marker.

(2) Continue straight on (south-south-east) along a path between the meadows. Cross a stream and head up to the edge of the woods. At the T-junction, turn left. When you reach the houses, the path gives way to a tarmac road.

Blue and white markings (rare)

(4) At the junction, turn left onto the Chemin de l’Yvette. At the end of the tarmac road, continue along a path. Head down into the Bois des Layes.

(5) At the bottom, turn right. Cross the Yvette and continue along Rue des Layes. At the junction, carry on straight ahead onto Route de Maison Blanche. After a few dozen metres, turn right onto Rue du Prieuré (no entry).

(6) At the next junction (blue road sign; the chapel of the former priory is a few metres opposite), turn left and take a path closed to motor vehicles. Walk uphill alongside a wire fence on the left-hand side. The path is steep and interspersed with wooden steps.

(7) At the top, at a T-junction, turn right. Head eastwards along a wide, flat path bordered (on the left) by the boundary fence of the Château de la Boissière Beauchamp grounds. At a junction (signpost, fire hydrant), continue straight ahead. After the “Château de Marchais” signpost, the path gives way to a stony track which, in turn, leads onto a small road.

(8) Follow the road to the right for about 200 metres. Just after a 20 km/h speed limit sign, leave the road and turn left onto a path that descends between the fields. At the bottom, follow a small road to the right.

Blue and white + red and white markings

At the entrance to the hamlet of La Recette, turn left. Cross the Ru de Pommeret. At the Stop sign immediately ahead, first turn right then left to cross the D58 ( a busy road) and take the Chemin de l’ancien Presbytère. The path climbs steeply. At the end of the street, climb a flight of steps and go through a gate to enter the cemetery adjoining Saint-Nom Church. Walk through the cemetery, keeping the church on your right, and exit at the other end.

(9) Then turn left, walk alongside a shaded car park, go through a metal gate and head up into the woodland. Ignore the^first turn-off on the right (Blue Cross and White Cross) and turn left along the path. At the next junction, turn right at an acute angle. Head south, ignore a turn-off on the left and follow the path downwards; the path becomes paved (near some old sandstone quarries).

Blue and white + red and white markings + black signposts (dedicated posts)

(10) At a junction, turn right (take care to spot this turn-off). The path winds its way between the hills and then descends in steep switchbacks interspersed with stone or wooden steps. At a fork in the road (information board), take the left-hand path and descend more gently. At the bottom, turn sharply left onto a wide path. Pass a large information board.

Black signposting (dedicated posts)

(11) Shortly after the sign, turn right onto a wooden boardwalk over the marsh. Go round the reed bed on the right and cross the Yvette via a footbridge. At the Pinguenet pond (sign), there is access on the left to a viewing platform above the water.

Immediately afterwards, at a junction on the boardwalk, turn right. Further on, the boardwalk gives way to a footpath. At a fork in the road, turn left and step onto a boardwalk once more. At a T-junction, turn right onto the “circular” path. Cross through wetlands and cross a few streams via wooden footbridges. Shortly after the information sign about the mill, turn left at a property and follow the path flanked by two fences. You’ll come out onto a road; follow it to the left (metal barrier). Take the old mill dyke, with the reed bed on your left.

Blue and white + red and white markings

(12) At a junction (signpost), turn right and follow the^GR®®11towards the Saint-Nom wash house. After about a hundred metres, you’ll reach the wash house. Cross the Yvette via a wooden bridge and, at the Fork in the road that appears immediately afterwards, take the path on the right. Winding your way beneath the chestnut trees, with a slope dotted with boulders on your left. Follow a fence on your right and pass the Moulin des Roches. Pass the Source aux Fées washhouse and continue through a beech forest.

Red and white markings

(13) At the crossroads (sign for ‘Forêt domaniale de Rambouillet’), follow the^GR®®11to the left. After about fifty metres, turn right and walk alongside a wire fence on your right. When you reach a house that looks derelict (marker post), take a path (not shown on the map) to the left at an acute angle, which climbs steeply into the forest (take care to spot this start). At a fork in the road, veer right and continue uphill more gently. Ignore a path branching off to the left and go through a small gate. You’ll come out onto a wider track; follow it to the left. After a small black gate, the track gives way to a tarmac road.

(14) After marker no. 4, turn sharply right onto a path that leads into the forest. Continue straight on towards the south-east, ignoring any vague offshoots to the sides. After a long stretch, ignore a path branching off to the right, turn left and emerge onto the D91. Follow the road to the left for about a hundred metres, then cross it at a small car park ( busy road). On the other side, take a path into the forest. At a junction, go straight on (ignore the blue arrow pointing to the right).

(15) At the junction by a private property on the left-hand side, turn right onto a hard-packed track towards Saint-Rémy-lès-Chevreuse. Walk between two fences, alternating between sections through the woodland and along the edge of a meadow. Pass through the hamlet of Jagny (with its beautiful houses) and continue eastwards. After a gentle descent, the gravel track gives way to tarmac and the gradient becomes steeper.

(16) After a bend to the right, turn left onto the Sente de la Tuilerie (take care to spot this turn-off). At the end, turn right onto Rue du 8 mai 1945. Then take the^second left, Rue Jean Mermoz. Walk past a hospital on your right and note the Château de la Madeleine high up opposite. At the end of the street, turn left.

Red and white + yellow markings

(17) At the junction, turn right onto Rue de Versailles.

Yellow markings

Ignore a dead-end on the left (leave the^GR®®). Then ignore a street on the right and turn left.

No markings

At the corner of a long building, turn right into a narrow lane towards the church. Go round the church on the right. Pass between a car park (on the right) and the church façade (on the left). Then leave the Prieuré Saint-Saturnin on your left. Pass under a porch and follow the main street to the right for about thirty metres.

Red and white markings

Take the^first left onto Rue des Mandars (pedestrianised). Cross the River Yvette (large wash house on the right).

(18) Follow the Promenade des Petits Ponts to the left (two branches of^{the GR®®11}split here; ignore the one heading off to the right). Walk alongside the River Yvette on your left and note the many small bridges leading to houses. At the^first junction, carry straight on.

(19) At^{the second} junction, turn right and walk past a car park on your right. At the next junction, turn left into a cul-de-sac and walk alongside the Yvette on your left. Ignore a path branching off to the right; the tarmac soon gives way to a path closed to traffic. Walk through meadows and a few small orchard plots.

(20) You’ll come out onto a path reserved for pedestrians and cyclists; follow it to the left, running parallel to a road. At the Stop sign (Ferme de Coubertin on the right, on the other side of the road), carry on straight ahead. At the traffic lights, cross the D938 (Rue de la République) and carry on straight ahead. You’ll immediately find Saint-Rémy-lès-Chevreuse station on your right (E).
To get back home:
- RER – Line B, towards Massy-Palaiseau and Paris.

Train timetables: see the Transilien website.

For motorists:
Arrange to have at least two vehicles, one at each of the car parks at the two stations, which are on different lines. Using just one vehicle would require a change between the two stations within central Paris. N.B. At Les Essarts-le-Roi, it is advisable to park in the cemetery car park, just before (1).

Hiking boots are essential. Wet sections between (2) and (3).

Water point in the Saint-Nom cemetery (9) (off in winter). Bars, restaurants and shops in Les Essarts-le-Roi, after (S), in Chevreuse between (17) and (18), and near Saint-Rémy-lès-Chevreuse station (E).

Notes regarding the Marais de Maincourt, between (11) and (12):
- Dogs must be kept on a lead and cycling is prohibited.
- The marsh is a protected site: please observe the other guidelines displayed on the large information boards.
- In wet weather, the wooden jetties are slippery.

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

Walk undertaken by the author on 5 October 2019.

(3) Source of the Yvette: statuette.

(6) Chapel of the former Priory of Yvette. The priory was founded in the 12th century.

(9) Saint-Nom Church (11th–12th and 16th centuries).

Between (11) and (12): Maincourt Marshes, with numerous information boards.

Between (12) and (13): the wash houses at Saint-Nom and La Source aux Fées; rocky outcrops; a beautiful chestnut grove; a beech forest with some remarkable trees.

Between (17) and (18), in Chevreuse:
- View of the Château de la Madeleine.
- Saint-Martin’s Church (16th–17th centuries).
- Saint-Saturnin Priory (10th–11th centuries).
- Wash house on the banks of the Yvette.

Between (18) and (19): the Promenade des Petits Ponts, along the River Yvette.