From Verneuil-sur-Seine to Cergy via the Hautil Forest

Starting point and access: Vernouillet-Verneuil station.
- Transilien - Line J, on the section between Paris-Saint-Lazare and Mantes-la-Jolie via Poissy.
Take the underground passage and the north exit towards the car park (ignore the south exit, which leads to Place Charles de Gaulle).

No signposts

(S/E) Walk along the railway line on your right and the covered car park on your left. At the corner of the car park, turn left, go through a chicane of concrete blocks and then the car park access barrier. Cross the street at the pedestrian crossing and enter the cul-de-sac opposite. The tarmac soon gives way to a path; walk along the Étang du Gallardon on your left. Turn right and continue along the pond.

Red and white markings

(1) At the end of the path, turn left onto Rue du Val de Seine and continue with the pond on your left. Follow the street as it curves to the right. At the end, cross Route de Vernouillet and take the alleyway that descends towards the Seine. Turn right and follow the river on your left. At the foot of the bridge, climb the stairs on the right. At the top, turn left and take the bridge over the Seine.

(2) At the end of the bridge, go down the steps on the left. At the bottom, turn right onto the quay and walk along the Seine on your left. At the stop sign, cross a small roundabout and continue straight ahead. At the next roundabout, turn right towards the Théâtre Octave Mirbeau. Take the cul-de-sac that goes around the theatre on the right and, at the end, climb a staircase. You will come out onto a street; follow it to the left. When you reach the post office, turn right into a street with a 30km/h speed limit and immediately turn right towards the church.

(3) Leave the marked route for a moment to enter the car park on the left and go around the church clockwise (otherwise, continue straight ahead and pass under the porch formed by the church itself). Return to the marked route and continue uphill along Rue Galande. Pass under the railway bridge.

(4) At the crossroads (Place des Marronniers), take the first street on the right (note that two^GR®® trails split here; ignore the signs to the left). At the stop sign, make a first turn left then right to climb a staircase (Rue Octave Mirbeau). At the top, ignore a street on the right and continue uphill on a footpath. Cross Rue des Temporêts and continue uphill on Rue Octave Mirbeau, ignoring all perpendicular streets.

(5) At the edge of a wood, turn right and descend slightly. At the fork, take the Sente du Battoir (path) on the left. At the next crossroads, continue straight ahead on the same path, which becomes tarmac. Ignore a turn-off on the left, continue along the path and, after a few metres, go down some steps on the right. At the bottom, turn left and cross Allée Georges Bizet. Continue straight ahead along the main avenue, going downhill and ignoring all the side streets.

(6) After the "J.S. Bach" bus stop, turn left and go up Sente des Marais. Pass some private gardens and then a chicane and continue along a path, first between two fences and then through shrubbery. Ignore any vague paths branching off to the sides and descend towards a house. At the T-junction, follow the street to the left. At the next junction, continue straight ahead along Grande Sente des Marais and descend into a residential area.

Between points (7) and (8), the purple route, which is supposed to represent the^GR®®2on the IGN map, is inaccurate.

(7) At the T-junction, go down the street on the right ( narrow pavements). At the small square, turn left onto Rue de Pissefontaine and pass in front of the Pasteur primary school. Opposite the church of Chanteloup-les-Vignes, turn left onto Rue du Général Leclerc. At the^first fork, follow Rue de l'Abreuvoir to the right and, at the^second fork, continue right on the same street. Cross Rue des Barrois on the right-hand side and you will come to a crossroads.

No markings

(8) Turn left onto Rue du Réservoir (let the^GR®® continue straight ahead). Cross Rue Pauline Soyer on the left and, at the fork immediately ahead, turn right onto Rue de la Forêt. Follow this winding street uphill, ignoring all the side streets and Rue des Champs on the right. You will come to a crossroads in the forest.

Yellow markings

(9) Continue straight ahead (due north) on a tarmac lane. When it turns left, leave it and pass a few boulders at the edge and then a forest barrier. Head north on a wide forest path, ignoring all turnings on the left (no access), walk along the wall of a property on your right and descend.

Red and yellow markings

(10) At the crossroads just after a small house on the right-hand side, continue straight ahead along a narrow path between two hedges. Continue along the edge of the field on your right. Cross a small road and follow Rue de Bellefontaine opposite (panoramic view on the right). Walk along a farmhouse on your left (beautiful gate and porch). Continue north-west on a farm track and immediately ignore a turn-off on the right.

(11) At the crossroads located directly below the medium-voltage power lines, turn left and leave the pylons on your right (no arrow or marker here). Walk alongside horse pastures on your left and enter the Hautil Forest. After a few metres, turn right and leave a pond on your left. Continue along the edge of the woods until you reach an orientation table.

(12) Continue north-west along the edge of the field on your right and go downhill. Pass through two forest gates in succession. At the corner of a wall, turn left towards a bus shelter. At the first pedestrian crossing, turn right (the purple line on the IGN map is inaccurate here) and take a path leading to the Ferme car park (even if inconsiderate motorists have parked right in the middle). Pass under a stone arch and ignore a path on the left. At the corner of a fence, turn left and you will arrive at the entrance to the Écancourt educational farm.

Yellow markings

(13) Continue straight ahead and walk along the farmhouse on your right. At the corner of the building, turn right and leave a pond on your left (information board). At the next fork (sign with map), take the farm track on the left. Walk alongside sheep pens on your right, then a shelter on your left. Ignore a path on the right and enter the forest on a wide, stable path. At the next intersection (plots nos. 5 and 6), continue straight ahead. After about 50 metres, when the stabilised path turns left, continue straight ahead on a dirt track (plot no. 5). Wind your way up through the forest and ignore any vague tracks on either side. You will come to a stabilised path again; follow it to the right.

(14) At the next crossroads (Chêne de l'Hautil tree felled on the left, information board), continue straight ahead. Descend into a sunken path then gently climb back up a sandy path through beautiful fern undergrowth. At the crossroads (picnic tables), continue straight ahead on a stabilised path between plots no. 8 and no. 7. Pass through a forest barrier, walk along a fence on your right (reservoirs) and pass through a second forest barrier.

(15) Turn immediately right downhill onto Rue de la Ferme. Walk alongside the farm and its dovecote on your left. At the crossroads (small castle on the left), go through a forest gate and continue straight ahead on a small tarmac road that slopes slightly downhill. At the next crossroads, turn left at an acute angle and walk alongside a wall on your left. At the end, make a first turn left then right to follow Rue Hérou (misspelled on the IGN map). At the end, turn left and, opposite No. 10, turn right onto a path between two walls. At the exit, continue straight ahead onto a street. At the next junction, turn right downhill.

(16) Cross the road to the left at the pedestrian crossing located in the chicane. Cross the small car park of the equestrian centre and turn left onto a farm track that soon turns right. Walk alongside horse pastures, first on your right and then on your left. At the end of the track, continue right along Rue André Parrain (ignore the yellow Rue du Maréchal Leclerc sign on the left; two^PR®® trails intersect here). At the roundabout, turn left and walk along the tennis courts on your right, then a school. At the crossroads, continue straight ahead, still on Rue André Parrain, and ignore the side streets and paths on either side.

(17) At the T-junction (church opposite at the top), follow Rue Vieille Saint-Martin to the right. Turn into the^{first street} on the left, Rue Charles Cavan. At the fork, take Rue de la Ferme on the right. At the T-junction, turn left. At the next junction, turn right onto Rue de la Grande Neuve. At the foot of the water tower, go through a forest gate and continue along a grassy path downhill. Go through a^second forest gate and continue along a narrow lane.

At the crossroads, take the^second left, Rue Vieille Saint-Martin again. Go downhill, walk alongside a golf course on your left and pass under some medium-voltage power lines. At the roundabout, turn left. Cross a residential area and ignore all the turnings on your left.

(18) At the large roundabout, continue straight ahead onto Rue des Coudraies. After Square Mozart, turn left with the street. At the traffic lights, turn right onto Boulevard des Chasseurs. Continue straight ahead and leave the signposts behind for a moment. At the next traffic lights, cross Boulevard Sainte-Apolline and turn right onto Chemin du Bassin.

Cross a large covered passageway, then a street, and continue straight ahead (you will see the signs again). Pass a barrier, then walk along a pond on your right. After a second barrier, cross Boulevard de la Crête and follow Rue du Désert aux Nuages to the right. Ignore the first street on the left and take the second, Rue de l'Embarquement. Walk past the bus station on your right and head for Cergy-le-Haut railway station, with access first to the RER and then to the Transilien (E).

To return home:
- RER - Line A, towards Paris.
- Transilien - Line L, towards Paris-Saint-Lazare.

Train timetables: consult the Transilien website.

For motorists:
Arrange to have at least two vehicles, one in the car park of each of the two stations, which are on different lines. With only one vehicle, travelling there or back by train would require a change at Paris-Saint-Lazare station.

Hiking boots are required. Potentially muddy sections between (6) and (7), between (9) and (12) and between (16) and (17).

No water sources identified along the route. Shelters and picnic tables in the Hautil Forest, between (13) and (15). Bars, restaurants and shops in Chanteloup-les-Vignes, between (7) and (8).

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

Hike completed by the author on 22 December 2017.

- Saint-Martin Church (13th-16th century) in Triel-sur-Seine.
- Saint-Roch Church (16th-19th century) in Chenteloup-les-Vignes, between (7) and (8).
- Bellefontaine farm with its porch, between (10) and (11).
- Orientation table and panoramic view of the Oise Valley (12).
- Pleasant walk through the Hautil Forest, between (12) and (15).
- Hautil Oak (14). This oak tree was felled during the storm of 1999, at an estimated age of 150 years, and left in place to show its natural decomposition.
- Beautiful farmhouse, dovecote and castle after (15).
- Saint-Martin Church (12th-18th century) in Courdimanche (17).