From Poissy to Conflans-Sainte-Honorine via the Forest of Saint-Germain-en-Laye

Starting point and access: Poissy station.
- RER - Line A, terminus of the section between Paris and Poissy.
- Transilien - Line J, on the section between Paris-Saint-Lazare and Mantes-la-Jolie via Poissy.
Take the Place Georges Pompidou / Centre-ville exit at the rear of the train when coming from Paris.

No signage

(S) When leaving the station, cross the square straight ahead, cross a boulevard and cross the small square that follows. Turn right into the street and pass between the entrance to an underground car park and the Municipal Police building. Cross Boulevard Victor Hugo and continue straight ahead on Rue Jean-Claude Mary.

At the crossroads (statue of Le Corbusier seated), take the^first left, Rue du Général de Gaulle. Go straight ahead along this shopping street, cross Boulevard de la Paix on the left-hand side, then cross Boulevard Devaux at the pedestrian crossing.

(1) At the corner of a large building, turn right onto Rue du 11 Novembre 1918. At the next corner (market hall on the right-hand side), cross a large square (kiosk) diagonally to the left towards the Town Hall. At the corner of the Town Hall, turn left, cross Rue du 8 Mai 1945 on the right-hand side and follow Avenue du Cep. At the crossroads, turn right onto Boulevard Louis Lemelle and walk alongside the police station.

When the boulevard turns right, turn left onto Avenue Albert Joly. At the crossroads (traffic lights), take the^second right onto Rue des Grands Champs. The street winds upwards; ignore a path on the left. At the crossroads, turn left onto Rue du Docteur Labarrière. Cross Rue de Beauregard at the pedestrian crossing on the left, climb a flight of steps and enter the Forest of Saint-Germain-en-Laye.

Red and yellow markings

(2) Two paths lead off opposite: take the one on the left, which starts at the foot of the information board with a map (the second path is not shown on the map). Continue straight ahead, heading south-east, ignoring any paths leading off to the sides. At the end (small metal gate), turn left and take the bridge over the platform of an old railway line.

(3) At the end of the bridge, take the middle path, slightly to the left, and enter the undergrowth. At a fork, take the left path. Immediately afterwards, you will come to a wider path and follow it to the right (north-east). Go through a forest gate and, at the stop sign, first turn left then right to cross the D190 at the pedestrian crossing. Immediately turn right and follow a cycle path for a few metres.

(4) Before the tree marked with the number 171, turn left onto a path that enters the undergrowth. At the crossroads, go straight ahead. The path widens to become a track. Ignore a path on the left.

No markings

(5) At the crossroads (plot no. 174), go straight ahead (leaving the^GRP® trail on your left). At the next crossroads, take the^second path on the right heading south, which starts at the foot of a tree bearing the number 176. In the hollow of a left-hand bend, you will find the Croix Pucelle. Continue along the widest path (ignore the path that branches off to the left) and you will soon reach a T-junction.

(6) Turn left (north-east; blue cross marker) onto a wide path. Continue straight ahead until you reach the Étoile Sainte-Anne (oratory high up on a tree trunk on the right). Take the^fourth path on the left (north-north-east).

(7) At the next crossroads, take the^third path on the right, which starts at the foot of a tree marked with the number 165 (tree located on the right-hand side of the path). Wind your way through a forest with beautiful fern undergrowth. At the end, turn right onto a wide path and head towards a forest barrier.

(8) Cross the road (take care), take the^second path on the left (marked with a blue cross) and pass by the tree with the Oratory of Saint Joseph hanging from its trunk. Keep heading north-east, go straight ahead at each junction and alternate between very short ascents and descents. You will eventually come to a road. Follow it to the left for a few dozen metres until you reach a large crossroads.

Be careful when crossing the junction. There are traffic lights (which you must obey) but no marked pedestrian crossing.

(9) Cross the D308. Then turn right to cross the N184. Walk past a restaurant on your left and leave the Croix de Noailles column on your right. Then turn left into a small car park, leaving the oak tree in the centre on your left. Before reaching the end of the car park, turn right, go through a forest barrier marked with an orange cross and follow a wide gravel path to the north-east.

Yellow markings

At the crossroads just after a shelter (Étoile du Tronchet), follow the path opposite, which starts just to the right of a tree marked with the number 125 and a sign prohibiting horse riders. After about 200 metres, turn right at the crossroads and continue to the next crossroads.

Red and yellow markings

(10) Turn left, follow the^GRP® Ceinture verte d'Ile-de-France (Ile-de-France Green Belt) heading north-northeast and pass four successive crossroads. The path gradually narrows. At the T-junction, turn right. Continue straight ahead (northeast) to Étoile du Chêne Capitaine.

(11) Then turn left into a very wide lane and take the bridge over the railway tracks. Continue straight ahead, pass a forest barrier, cross a road and continue straight ahead. After about 20 metres, turn left onto a path through the undergrowth. At the end, ignore the tarmac road on the left and continue along a wire fence.

(12) At the corner of the wire fence, turn left. Follow a good path and ignore the faint tracks on the left. After about 400 metres, at a clearly marked crossroads, turn left.

(13) At the crossroads (plot no. 60), turn right. Follow a path through the woods and, at two crossroads with less marked paths, go straight ahead. At the next crossroads, take a larger path on the left (west-southwest).

(14) At the crossroads (forest house on the left), turn right at an acute angle and follow a wide stony path. At Étoile du Renard, take the^third path on the left (north). Go straight ahead and descend slightly to reach Étoile Sainte-Honorine.

(15) Take the^second path on the left and you will soon reach the edge of the Étang du Corra. Then turn right and follow a wide path. Walk along the left-hand side of the pond (fenced or unfenced depending on the location) and ignore all paths on the right. Stay as close as possible to the pond (the purple line on the 1:25,000 map is not entirely accurate) and note the wall of a property on the right.

(16) At a small beach at the end of the pond, turn right. Cross two tarmac paths in succession, continue straight ahead and pass a picnic table on your right. Ignore a path coming from the left and turn right. At the end of the path, go through an opening in the wall, which leads to a road. Follow the road to the right onto a cycle path.

No markings

(17) At the foot of a sign marked "Site Val de Seine", turn left to cross the road. Immediately turn right onto the gravel cycle path towards Conflans-Sainte-Honorine. Go through a chicane and continue on the cycle path, which initially runs parallel to the road but then veers away from it. At the stop sign, turn left onto the tarmac road.

At the next crossroads, turn right, then immediately left with the road and cross a housing estate. After about 250 metres, take a gravel path on the left that crosses a lawn. At the end, turn right, go through a gate and turn left.

Red and yellow markings

At the stop sign, follow a small road to the right that runs parallel to the N184. When the small road turns left, take the footbridge on the right to cross the Seine. At the end, turn right. Go down the steps on the right and join the Chemin du Touage along the banks of the Seine (towing is a special technique for hauling boats).

Red and white markings

(18) Follow the quay westwards, pass under the road bridge and walk along the Seine on your left. Pass under the railway bridge (just before this bridge, if you are in a hurry, you can take a street on the right that leads to the station in 500 metres). Stay as close as possible to the river and you will reach its confluence with the Oise (war memorial).

No markings

(19) Turn right and follow the Oise on your left. Pass under the road bridge. Immediately afterwards, turn right onto Rue du Relais de Halage. After about 50 metres, turn left and pass between a car wash (on the left) and a fast food restaurant (on the right). Climb a staircase and then turn left to reach Conflans - Fin d'Oise station (E).

To return home:
- RER - Line A, towards La Défense and Paris or Cergy (immediate access).
- Transilien - Line L, towards Paris Saint-Lazare or Cergy (immediate access).
- Transilien - Line J, towards Paris-Saint-Lazare or Mantes-la-Jolie (go to the end of the RER platform and climb the stairs leading to the perpendicular platform for line J).

Hiking boots recommended.

No water sources identified along the route.
(S) In Poissy, shops near the station and numerous shops on Rue du Général de Gaulle.
(E) In Conflans, just before the station, there are bars and restaurants.

In the Forest of Saint-Germain-en-Laye, during the hunting season (November-February), avoid Tuesdays, when battues (hunts) are organised.

Hike completed by the author on 7 September 2019.

In Poissy, from (S) to (2):
- Market hall (1).
- Town Hall Square, featuring a bandstand and four small sculptures.

In the Forest of Saint-Germain-en-Laye, between (2) and (15):
- Mixed forests, fern undergrowth... It is not uncommon to see a deer or roe deer passing by on the way...
- Croix Pucelle (6), dating from 1456 (the year of Joan of Arc's rehabilitation), overturned in 1793 and re-erected in 1848.
- Sainte-Anne Oratory, a "Quimper" style earthenware statuette.
- Saint Joseph's Oratory (8), wooden statuette.
- Croix de Noailles (9), built in 1751 by the Duke of the same name, destroyed in 1793 and restored in 1953.
- Pavillon de la Muette (13).

From the Corra Pond to Conflans, between (15) and (E):
- Étang du Corra.
- Chemin du Touage along the banks of the Seine.