From Palaiseau to Orsay via the Bois des Gelles

Starting point and access: Palaiseau-Villebon station.
- RER - Line B, on the section between Paris and Saint-Rémy-lès-Chevreuse.
Take Exit 1, Boulevard Nicolas Samson, on the side of Platform 1, travelling from Paris to Saint-Rémy-lès-Chevreuse (if arriving from the opposite direction, Platform 2, take the underpass).

No signposting

(S) On leaving the station, cross the roundabout, take Rue Lazare Hoche opposite (against the flow of traffic) and head downhill. Cross Rue de Paris at the traffic lights and continue straight on, downhill, along Rue Lazare Hoche. At the end, turn right towards Villebon, immediately ignore the streets on the right and follow Rue George Sand as it curves to the left. Cross the Yvette and you will immediately reach the Rond-Point de l’Europe.

Red and yellow markings

(1) Go round the roundabout on the right and immediately go down a flight of steps on the right. At the bottom, turn left and walk along the Yvette on your right.

Red and white + yellow markings

Ignore a red and yellow arrow pointing left and stay on the gravel path as close as possible to the river. Walk alongside a lawn with a playground. Join a narrow lane and follow it to the right, keeping a wall on your left. At the crossroads, take the^first right (dead end). Ignore a footbridge on the right, turn left and follow the Chemin des Foulons along the Yvette. Continue down a narrow lane and pass the foot of a large red-rendered building. At the Stop sign, turn right.

No signposting

(2) At the traffic lights, turn left and head uphill. At the corner of No. 15, take the discreet path on the left (be careful to spot this start). The path immediately turns left then winds between walls and fences, alternating between gentle climbs and flat sections. Finally, head downhill to emerge onto a street (Rue du Bas de la Ferme on the map).

Then turn right and immediately right again to follow the footpath which starts with a flight of steps. At the end, cross the road at the pedestrian crossing (Rue des Maraîchers) and follow it to the right. At the corner of No. 10, turn left towards the Centre Culturel Jacques Brel and cross a small car park. At the far end, climb a flight of steps and then follow a paved path that winds its way up, with a handrail in the middle.

(3) At the top, head straight ahead into the tunnel that passes under the D188 and enter the Saint-Exupéry Sports Centre (if the gate is closed, see an alternative route in the practical information). As you exit the tunnel, turn right and walk past a football stadium on your left, then some tennis courts. At the corner of the last court, turn left and walk past a large building on your right.

At the corner of the building, turn right and walk past the sports hall and town hall on your left. Leave the sports centre through a gate and continue along a road, ignoring the car park entrances on either side. Walk past the Leisure Centre (on the left) and arrive at a junction just before the bridge over the D188.

(4) Then turn sharply left, pass through a forest gate and enter the Bois des Gelles Departmental Forest. Follow a good path slightly uphill and ignore all the side paths. Cross a stream then climb steeply up the path interspersed with steps (waterfall on the left). At the top, pass a hairpin bend and veer left to join a wide path.

Yellow markings

Follow the path to the left, then immediately turn right with it and climb gently. Ignore a path branching off to the left and turn right with the path. Ignore a flight of steps leading down to the right, turn left with the marked path, pass the base of an antenna on the left and continue on level ground. Pass the base of an information panel on the right-hand side and arrive at a T-junction (isolated oak tree and bench on the right).

No signposting

(5) Then turn right and walk alongside a fence on your left and a lawn on your right. Pass under a gateway.

Yellow markings

Continue due west along Rue Millet and pass by a water tower. It is best to take the path running parallel to the street on the left-hand pavement and ignore all turn-offs to the right. The path crosses a road via a footbridge and then runs alongside a small fenced-off wetland area below on the left. At the end, cross a tarmac section, pass between two boulders and follow a path for a few metres.

Unmarked

(6) At the T-junction (bench, litter bin), follow a path to the right (ignore the signposting heading left). Descend slightly. At the entrance to a sort of small, cluttered ravine, veer right to climb a small rise. Two parallel paths then appear (the map shows only one): choose the one furthest to the left, which stays higher up and is easier to walk on (the one on the right is lower down). Continue descending.

At a fork in the road, turn right and stay on the “ridge”. Join the path you left earlier and follow it to the left, still descending. Cross a wide track and continue straight on for about thirty metres.

Yellow markings

Turn right into the narrow tunnel that passes under the D188. At the tunnel exit, ignore a faint path on the left and continue along the wide track.

No markings

(7) At the junction, turn left and head downhill. At the next junction (birch trees), turn left again. Head slightly downhill, cross a stream and continue on level ground. At a junction (map of the Orsay Communal Forest on the left), continue straight ahead and head slightly uphill. Further on, ignore a path on the right at the corner of a fence and continue straight ahead.

Yellow markings

(8) At the next junction, continue straight ahead again. Walk alongside a fenced-off building on your right. At the corner, turn right and walk alongside the N118, which runs higher up on the left (you can hear the traffic).

No markings

At the end of the path, turn left and go under the N118 bridge. Follow Rue de Paris to no. 58. Then turn right, cross the road at the pedestrian crossing and follow a tarmac path opposite, running parallel to a one-way street. You’ll come out into a car park; go to the far end, then turn left and walk along a low wall on your right (note the turreted building on the right). Just before the car park exit, go through a small gate on the right and go down some steps.

At the bottom, at the foot of the turreted building, turn left. Go straight on, go through a metal gate and then a stone archway. You’ll come back to Rue de Paris; follow it as it continues (slightly to the right). At the crossroads, on the corner of the post office, go straight on and follow Rue Verrier. Cross the road at the pedestrian crossing and continue straight ahead along a footpath. At the end, turn left. At the roundabout, continue straight on into Boulevard Dubreuil. Walk slightly uphill and you will soon reach Orsay-Ville station on your right (E).

To get back home:
- RER - Line B, towards Saint-Rémy-lès-Chevreuses (direct access to platform 1) or Paris (take the underpass to platform 2).

Train timetables: see the Transilien website.

In wet weather, the paths through the woods may require walking boots.

Bar just outside Palaiseau-Villebon station. Bars, restaurants and shops in Orsay town centre, between (8) and ::A.

Alternative route:
At (3), if the gate to the tunnel and sports park is closed, turn right. Take Rue Liederbach, running parallel to the D188. At the end, turn left onto Rue Las Rozas de Madrid. Cross the bridge over the D188 and rejoin the main route at the entrance to the Bois des Gelles departmental forest (4).

Additional information:
This walk can be extended by taking the Petite circular orcéenne through the woods and along the Yvette promenade. Follow this route to its end point (8). Then turn sharply left and follow the second route from its starting point (3). Continue in this way to Orsay-Ville station, the terminus of both routes. The total distance is approximately 11 km.

A detailed map is useful (at the very least, the one accompanying this description).

Walk completed by the author on 15 January 2022.

- Yvette walk, between (1) and (2).
- Waterfall in the Bois des Gelles, between (4) and (5).
- La Bouvêche, between (8) and (E), a farmhouse belonging to the former Château d'Orsay, dating from the 15th century and now housing a cultural centre.