Autour de Beauvais et Mondeville par le Rocher du Duc

To reach the car park: take the A6 motorway, exit 11, then take the D948 towards Milly-La-Forêt. About 7 km after Auvernaux, turn right onto the D75 towards Champcueil and Chevannes. Park in the car park 300 m on the left.

(S/E) Leave the car park via the blue-marked trail that climbs up the rocks opposite the car entrance (north side). At first, the trail follows the main path that winds between pine trees and beautiful rocks, but at the end of the climb, in front of large rock faces, it turns right before starting to descend. Do not hesitate to turn back if the markings disappear. At the end of the descent, the trail winds around the foot of the massif, turning left at several junctions. After a straight stretch and a gentle descent heading west-northwest, you will reach a junction where the markings turn 90° to the left. The forest thins out on the right.

(1) Leave the signposting and go straight ahead to quickly find the boundaries of private properties. Continue to the tarmac forest road from Beauvais to Loutteville. On the road, turn left towards Beauvais, following the footpath/cycle path on the right of the road. After about 350 m, and 3 rocks on the right-hand side of the path, look for the passage on the right that enters the forest. A sign hidden behind the trees indicating the paths becomes visible. Go back and cross the road opposite the sign to see the menhir (*) at the entrance to the forest, on the other side of the road.

(2) Retrace your steps to enter the forest to the left of the sign, behind the barrier, and find the path parallel to the road. Take it to the left, south-west. The blue markings will appear further on. Follow them uphill, ignoring all the paths on either side, until you find the GR®11 (white+red).

(3) Follow the GR® on the right, which crosses the plateau and the ponds. At a fork, take the left path (do not take the descent on the right on the other side of the plateau) and stay on the white and red markings until you reach the Tour du Buisson (*).

(4) Continue following the GR® trail, ignoring a path that descends to the right. Ignore a path on the left and a little further on you will come to a well-marked crossroads with stone barriers on the GR® trail and a path coming from the left, following the edge of the woods: this is the (buried) aqueduct of La Vanne and Le Loing (*). Continue on the GR® until you reach the wooden barrier at the end of the small clearing.

(5) Leave the GR® by turning right onto the aqueduct path, where you will immediately find steps. These are the 100 steps of the aqueduct (buried). Go down the steps and follow the aqueduct until it emerges from the forest through a gap in the trees, near a round and rectangular masonry structure used for aqueduct maintenance.

(6) Continue to follow the aqueduct, which will turn left due west. Continue to the small road from Champcueil to Mondeville. Cross this road and continue until you cross the path coming from Champcueil on the right, which is about to climb into the woods on the left.

(7) Leave the aqueduct and turn left, climbing into the woods. Just before the top of the woods, find a yellow-marked trail perpendicular to the previous one.

(8) Turn right onto the yellow-marked trail. Follow the edge of the woods on your right and re-enter the woods. As the yellow markings are fading, follow the main trail with the D153 fairly close on your left. Continue until you reach the D153, cross it and follow it to the right until you reach a gate (on the left) with a pedestrian crossing and a "no dumping" sign.

(9) Go through the gate and follow the yellow trail (markings disappearing) that runs along the edge of the woods. 500 m further on, do not enter the woods on the right, but stay on the path that turns left across the fields towards the Malvoisine farm (*). In front of the farm, rejoin the GR® (white and red) and turn right towards the forest. The path joins the woods and runs alongside them for 150 m.

(10) At the junction of the GR®11 and GR®11C, turn left (south) along the woods on the GR®11. The GR® turns right, then left along the woods, then joins a perpendicular path that enters the woods. In hot weather, you can look for the path that follows the clearing in the shade of the trees.

(11) Turn right and follow the GR® trail into the woods. After a long, almost straight stretch, be careful at the crossroads at the bottom of the descent: the GR® signpost will indicate a slight left turn.

(12) Keep following the GR® which turns left before turning right again. At the end of the plateau, there is a long, fairly steep descent. At the bottom, after 200 metres of almost flat ground, follow the GR® which turns 90° to the left. Continue on the GR® which crosses several paths, following the hollow of the valley. Caution: when the climb becomes steeper with rocks on the right, the GR® trail turns almost 180° to the right. Follow it up the climb that winds through large rocks to reach the summit of Roche aux Dames (difficult climb in places. It is often possible to bypass the most difficult sections).

(13) Take the GR® trail, which descends gently to rejoin the previous path and pass between properties on the right and a campsite on the left. Follow it to Mondeville. In the centre of the village, the GR® trail turns right just before the church. Leave it to reach Mondeville church (*) just after on the left.

(14) Take the Grande Rue towards the east. On leaving the village, when the Grande Rue becomes the D153 which branches off to the right towards Boutigny, turn slightly left onto the Route de la Padôle. Continue straight ahead across the fields towards La Padôle and join the Bois de la Garenne de la Padôle. Here you will find the yellow PR® coming from the left along a small road. Continue straight ahead towards the hamlet and pass between the woods and La Padôle (*) following the yellow PR® sign.

(15) Continue on the path marked in yellow that runs along the woods on your left. The path enters the woods in a left-hand bend to go around the old Padôle quarry. After a right-hand bend, you will reach a crossroads.

(16) Take the sandy path marked in yellow on the left that descends into the woods. Continue through the woods and take the path opposite when a marked path arrives from the left. Exit and follow the woods until the path joins the buried aqueduct with the signpost that branches off to the left to go back up into the woods.

(17) Leave the signpost and continue straight ahead to Beauvais. Enter Beauvais via Chemin de la Forêt, continue along Rue de Milly, then turn left onto the^first street, Rue du Puits (sign opposite, but not very visible). When you reach Rue du Gazon, turn left until you reach the crossroads at Place Adeline.

(18) Turn right onto the square and continue to the^first crossroads, then turn right onto Rue de la Chapelle. At the end, turn left and follow the^GR®® (white and red) signs, Rue de la Couture, then Chemin des Postes, until you approach the telegraph site (*). At a crossroads, near the tarmac forest road, the GR® turns right and climbs up the rocks.

(19) Climb up the rocks on the right on the GR®. At the top, keep following the GR®: be careful to follow the markings. The^GR® joins the Blue trail. Leave the Blue trail on your left and continue on the double Blue-White and Red markings through the rocks and viewpoints. Continue until the GR® leaves the Blue trail and descends to the right (south)

(20) Do not descend! Leave the GR® and follow the blue trail to the left (follow the markings carefully). The trail winds between the rocks, with descents and ascents towards the viewpoints. Towards the end of the plateau, it goes around the last rocks on the right before beginning the descent.

Be careful at the bottom, as the blue trail joins the wide grassy path that leads opposite towards the car park on the D948. Do not continue opposite, but stay on the blue trail, which turns sharply left (lightly marked). Continue on the blue trail until you see the car park below on your right (S/E).

N.B. In the rocks, the automatic calculation underestimates the twists and turns of the route: allow for 23 km, 350 m of elevation gain and 7 to 8 hours with a picnic.
You can picnic at the top of the Rocher des Dames or on the right as you leave Mondeville, on the rocks behind the fire station.

There is no water source. Given the numerous climbs, bring 2 litres of water in hot weather.

Strangely enough, the GR® family trails are the most difficult, especially the climb up Rocher aux Dames. However, it is well worth the effort. If you are uncomfortable with difficult climbs, you can skip this section by continuing straight ahead instead of turning right at the start of the climb. Another option is to go straight ahead and then, when you rejoin the GR®, take it backwards to make the climb easier.

(S/E) The beautiful Rocher du Duc massif.

(2) Menhir on the forest road at the entrance to the forest. Excavations have confirmed the megalithic nature of this stone. The ceramics found in the foundation hole date from the Late Bronze Age (1500-2500 BC), which is unusual for the erection of menhirs and has led to a scientific publication.

(3) Mares de la Platière, classified as a "Sensitive Natural Area" due to the botanical interest of the site. Historical interest: the owner was obliged to allow the inhabitants of neighbouring villages to use it for washing clothes and watering their animals. It should be noted that there is little water on the plateau.

(4) Tour du Buisson, recently restored with an orientation table in the tower. The Tour du Buisson is located on land that belonged in 1824 to Antoine Louis Bréguet, the famous Parisian watchmaker. This brand, created by Abraham Bréguet, the inventor of the wristwatch, remains renowned but is now based in Switzerland. Breguet was also an inventor of astronomical equipment, hence the interest in this tower, which was built to serve as an observatory. The Breguet family also owned the Château du Buisson near Champcueil. The Breguet family later turned their attention to aviation (probably as an extension of their interest in astronomy). Since 1971, Bréguet aircraft have been part of the Dassault group, whose official name became AMD-BA (DA since 1990).

(5) Stairs of the Vanne and Loing aqueduct. Built between 1867 and 1874, the aqueduct is 173 km long. The water that supplies Paris flows deep underground here. The "100 steps" were built to facilitate the construction and maintenance of the aqueduct. There are two other "100 steps" sections in the Coquibus.
The Vanne aqueduct comes from Burgundy. The Loing aqueduct comes from various sources in the Loing and Lunain valleys near Nemours. These two aqueducts, along with the Voulzie aqueduct from Provins, meet in the Fontainebleau forest at a water treatment plant. The water then flows to the Montsouris reservoir in Paris. Now, the water from the Vanne is diverted to the Haÿ les Roses reservoir.

(6) Masonry structures with access doors to the aqueducts for maintenance.

(9) In the fields: Malvoisine farm. To the left of the farm is a tower which is the geodetic point and the highest point in the region (152.3 m). This location, in conjunction with Amiens, was used to determine the length of the meridians, which in turn gave us the length of the metre.

(13) View from Les Roches aux Dames.

(14) Mondeville Church, 13th and 15th centuries, listed building.

(15) La Padôle. Originally, the quarry workers' dwellings were grouped around a pond.

(19) The name of the cottage comes from a Chappe telegraph, the ruins of which can still be seen on the plateau overlooking the site. The Chappe aerial telegraph system, whose installation began in 1793, was the first telegraph system and remained in use until the mid-19th century. Champcueil, located on the Paris-Lyon line, was in service from 1805 to 1850. It received messages from other buildings located to the north in Vert-le-Grand (towards Paris) and to the south: the Fleury-en-Bière telegraph in the Turelles forest, between Fleury and the Château de Courances. The Fleury telegraph station itself received messages from the south-east from the Noisy telegraph station, on the Belvédères circuit in the 3 Pignons.

(19) + (20) A beautiful route through rocks and viewpoints in the Rocher du Duc.