From Noisy-le-Grand to Gagny and Mont Guichet

On arrival at Noisy-le-Grand Mont d’Est RER station, take Exit 3 – Bassin.

(S) Leave the station opposite the pond. Follow the pond to the left (northwards), go round it to cross the dual carriageway at the traffic lights, then walk alongside the pond via the Promenade des Mares Blanches. At the end of the Promenade, cross the road and continue straight ahead down the path between the two blocks of flats. After a short zigzag, you’ll reach a pretty semi-circular square at the edge of the Allée des Petits Jardins. At the far end of the square, take the Mail (heading north) to its end.

(1) On your right is the Espace Michel Simon. Opposite the entrance, take the wide avenue leading to the elegant Noisy Town Hall. Walk alongside it on your right to admire the panoramic view from the terrace, then go down the steps towards the small garden with its ponds. Cross the boulevard, then take the Promenade François Mitterrand opposite (one-way street). Take the first street on the left. When you reach the end of Rue de la Terrasse, turn left uphill, then right, and right again to reach the church forecourt.

(2) Go inside to admire the stained-glass windows, which are in various styles and from different periods, then walk round the church along its north façade to enter the cemetery and head due east towards the small exit gate onto Rue du Vieux Moulin, which you follow down to the left. Head back up the^{first street} on the right (Rue du Miroir d’Eau) until you reach the Promenade François Mitterrand, which you follow downhill to the left. Take the first turning on the left to reach the pretty pond surrounded by trees.

(3) Go down the steps to the north, admiring the ‘spring’ and its Napoleonic-style grille as you pass, and reach Rue des Sports, which you follow eastwards. At the junction, turn left into the street, then immediately take the path on the right which leads into a grove and emerges onto a lawn at the foot of a large block of flats. Continue to the left, reach the crossroads and take the Allée de la Grotte straight ahead (heading east). At No. 1, you’ll pass one of the key sites of the local Resistance (Jacques Claveau’s hideout). At the junction with the Allée Caroline (which branches off to the right), take the path straight ahead leading to the banks of the Marne.

(4) Follow the right bank of the Marne as far as Gournay Town Hall, housed in a château well worth a visit.

(5) Don’t forget to admire the venerable catalpa tree in the grounds, with its gnarled trunks and branches, then turn back along the Marne to return to the metal footbridge, crossing the Marne and its canal. As you leave the footbridge, turn immediately right to reach the canal, pass under the footbridge and follow the canal downstream. After about 200 m, turn right onto the path leading to the access road for the Parc de la Haute-Île. Take this road on the left, which climbs slightly, and you’ll reach the park entrance, which spans the canal via a bridge.

(6) There are several possible routes through the park. The most ‘rural’ one (with sheep, goats and cows) is the central path known as the ‘friche’. Whichever route you take, head towards the exit at the western end of the park. Continue along the canal to reach the Neuilly lock and its small marina.

(7) Cross the bridge, follow the canal upstream on its right bank, and, after the football pitches, take the path heading north. When you reach the tarmac, turn right; then, when you reach the gates, continue north on the path that runs between the fence on the right and the built-up area on the left. Cross over the D 934 and continue along the path that runs alongside the boundary wall of the former psychiatric hospital. You will then enter the Parc du Croissant Vert. Continue northwards along the main path, which runs along the edge of the park, until you reach the main entrance

(8). Leave the park, turn right and follow the park’s northern boundary until you reach Lac de la Mare Blanche. Walk round the lake, then turn left onto Avenue des Pêcheurs. Then, in turn, take^{the 2nd} right,^{the 1st} left (Boulevard de l’Espérance),^{take the first} right (Place des Fêtes) to reach a rather handsome manor house at the crossroads, which appears to be disused. Opposite, take Avenue de Toulouse. At the end, turn right, cross the N 302 and take Rue du Chemin de Fer, which leads to Chénay-Gagny station.

(E) Here you have two options:
- head back, either towards Paris or by bus, to return to the starting point in Noisiy,
- continue along the street to the footbridge, and use it to cross the railway tracks. Then turn immediately right, then left onto the Vieux Chemin de Meaux, until you reach the passageway between the Théodore Monot secondary school and the next building.

(9) Opposite this passage, take a path heading west-north-west. Pass under a high-voltage power line and reach a short but steep descent, a remnant of the excavations in the old quarries. Go round an abandoned (but squatted) building and follow the path as it climbs the slope. At the top, you’ll come to a path; take the one on the right. You’ll soon come across a deep chasm (10 m?) on the left, which is currently unprotected: Caution – Danger. A little further on, you’ll reach the impressive entrance to a gypsum mine tunnel. It’s advisable not to venture too far inside: the rock is crumbly.

(10) Continue along the main path which, after a circular loop to the east, heads due north and climbs up the side of the hill. Keep following the main track along the hillside, which veers north-east, then east, zigzagging whilst remaining more or less within sight of the houses or property fences on your left, and around the 100m bend. At one point (about 2km past the mine, reach a descent and then head south-east) you’ll come to a T-junction.

(11) Turn right onto the correct path which descends, bordered on the left by a fairly deep ravine, into which the path enters as it curves to the left. You will then reach the foot of a cliff, or rather the former working face of the gypsum quarry, the access to which is protected by a wooden fence. Take the path opposite the cliff (south-west), and you’ll soon reach a fence: turn left and walk alongside a building site. At the^first junction, turn right onto the correct path which runs between the pasture fences. Follow this path, which curves widely before approaching the high-voltage power lines, and pass under the first two.

(12) At the crossroads just before reaching the foot of a pylon on the^third line, turn right, pass under the other two lines, and complete a circular route by returning along the route you took on the way in, before passing through the mine entrance again.

(10) Then retrace your steps along the route you have already taken to return to Chénay-Gagny station (E)

Between the two stations, the walk can be done in light walking shoes. However, particularly in wet weather, the paths through the former gypsum quarry require shoes with good grip: the ground can be very muddy and slippery.
Please note: dangerous areas are neither signposted nor protected: exercise extreme caution, especially if there are children present.