In the Massif des Trois Pignons

The Massif des Trois Pignons is situated on the edge of Fontainebleau forest. The walk takes you past the Rocher des Guetteurs, the Sables du Cul du Chien, the Diplodocus, and the Rocher de la Tortue.

Technical sheet

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  • Walking
    Activity: Walking
  • ↔
    Distance: 11.93 km
  • ◔
    Average duration: 4h 10 
  • ▲
    Difficulty: Moderate

  • ⚐
    Return to departure point: Yes
  • ↗
    Vertical gain: + 267 m
  • ↘
    Vertical drop: - 268 m

  • ▲
    Highest point: 121 m
  • ▼
    Lowest point: 67 m

Photos

Description of the walk

Canche aux Merciers car park — Croix Saint-Jérôme 2.7km

From the end of Canche aux Merciers car park, near the information boards, the Canche aux Merciers footpath, a wide, grey sand path, leads due west towards the site of the same name. Follow signs for "Départ promenade de la Vallée d’Arbonne" until you reach the Carrefour de la Charme crossing. Located 300 metres from the car park, the site of Canche aux Merciers is very popular because, in addition to a large "sandy beach", there are many rocks where children and adults alike can practice rock climbing.
At the crossing (1), turn left onto the Chemin de la Charme, which runs alongside the Canche and and has yellow waymarks for the Vallée d’Arbonne walk. Follow the path until it reaches the Maison du Poteau crossing. At the Maison du Poteau crossing, leave the yellow waymarks and carry straight on, still on the Chemin de la Charme between forest plots 116 and 115. After 400 metres, at the start of the descent, the path crosses the Denecourt-Colinet n°16 footpath, which is waymarked in blue. The white sand gradually becomes a more and more striking feature of the landscape around you especially to the left of the path. Another 450 metres further on (2), the path crosses the "25 Bosses" (25 Bumps) footpath (red waymarks): stay on the Chemin de la Charme which runs between forest plots 116 and 117.
Before long, you will see the red waymarks of the 25 Bosses footpath (3). From here you will follow the red waymarks until the path descends from Rocher du Guetteur. In the meantime, you will first go past the houses of the neighbourhood of Croix Saint-Jérôme.

Croix Saint-Jérôme – the Sables du Cul du Chien: 3km

This is the hardest part of the walk as you will now climb 4 “bumps” or hills which are each about 50 metres high and have steep slopes covered in rocks that the path sometimes winds between and at other times takes you straight over.
The first hill is called Roche au Four, and it has beautiful views of the region and above all of the next series of hills, the 3 Pignons, to which the Massif des Trois Pignons owes its name, and which are actually 4 in number.
The path goes quickly down and crosses the wide track of the Vallée Close (4). Then there is a climb up to Rocher de la Souris, immediately followed by a rugged descent, and then another climb up to Rocher de Jean des Vignes. The following hill, the Rocher du Guetteur, is a little further away and the path makes a long loop to get there. The climb is steep here too. When you reach the top, there are two points of interest: a kind of chalice surmounted by a cross carved into the sandstone and, just beside it, a strange rock resembling a seat, hence the name of the Rocher du Guetteur (the Watchman’s rock) given to the hill. There are beautiful views from here over the forest and the Sables du Cul du Chien. Once again, the descent among all the rocks is tricky.
When you reach the bottom (5), leave the 25 Bosses path and instead follow the unmarked path to the left. This path winds gently down through the pine trees until it reaches the crossing with Chemin du Mont Pivot. Take the left-hand fork and follow the path between forest plots 136 and 137. The path will take you around the bottom of Rocher du Guetteur before arriving at the Chemin des Sables du Cul du Chien. At the crossing, turn right onto the Chemin des Sables du Cul du Chien. Leave the hills you have climbed behind you, cross the wide track of the Chemin de la Plaine de Jean des Vignes (6) and go straight until you reach the famous "sea" of white sand. This really is one of the most beautiful places in the Trois Pignons forest!

The Sables du Cul du Chien - The Diplodocus: 1.4 km

As the stretch of sand is vast, it is not easy to find the path again to carry on as there are no waymarks (hence the importance of having an IGN map and a compass with you).
So, when you get to Les Sables, the easiest way is to walk along the sandy beach on the right to see one of the strangest rocks in the forest, the Bilboquet. The land rises slightly as it reaches some rocks and birch trees which mark a kind of separation from a second large stretch of sand. At the entrance to the second beach on the left, with a wooden fence around it, is the Bilboquet. It resembles the shape of a dog’s head. Erosion, and above all, rock climbing (now prohibited) have worn it away somewhat. There are other beautiful rocks in the nearby area, including one that looks like an elephant's head, but it is hard to find: keep walking for another 60 metres to the southwest, with the Bilboquet behind you, and then turn left onto a kind of wide sandy path that leads between two birch trees to find the elephant, which is about fifty metres further on.
To leave the Sables du Cul du Chien, walk along the edge of the sandy beach to the southwest with the Bilboquet behind you until you find, 160 metres further on, the trace of a path (7). Turn left. The Chemin de la Roche aux Sabots, marks the boundary between forest plots 143 and 144 and runs around the rocks of the Sables du Cul du Chien from the south. When you reach a kind of T-junction, take the path to the right (the path to the left takes you to a large sandy slope) until you reach the Ancien Chemin de Melun (8). Take the path opposite you with white waymarks, which marks the boundary between forest plots 144 and 145. The path leads to the Rocher du Général, where it joins the Chemin de la Plaine de la Mée. Turn left onto it and carry on until you reach the crossing with the Chemin du Rocher Fin. Turn right and follow the path for about 200 metres. The Diplodocus is not far away (on the right of the path). Again, this is a wonderful rock climbing site with impressive and remarkable sandstone blocks, especially the huge standing stone known as Diplodocus.

The Diplodocus – The Tortue: 1.3km

Walk out from the rocks due East, following a branch (or variant) of the 25 Bosses path, which serves as a shortcut (discrete red and white waymarks): cross the Chemin du Rocher Fin, and then the Chemin de la Mée and, 70 metres further on, you will reach the Chemin de Melun au Vaudoué which runs between forest plots 148 and 149 (9). Take the left-hand fork and follow this path for 500 metres until you reach the crossing with the 25 Bosses footpath. Turn left onto the 25 Bosses footpath (red waymarks) and after 300 metres you will reach a rock resembling a turtle: the Rocher de la Tortue (10).

The Rocher de la Tortue – Canche aux Merciers car park: 3.6km

Retrace your steps until you get back to the crossing with an unnamed path on the border between forest plots 128 and 148, then take this path to the right. The path eventually joins the Chemin de la Mée, which you then take north. A little further on, the GR1 joins in from the left. Follow the path with its very characteristic red and white waymarks for 1.6 km until you reach the Sapeurs du Génie crossing. In the meantime, you will leave Chemin de la Mée to climb up onto a beautiful plateau covered with pine trees and heather after crossing the 25 Bosses footpath once again. At the Sapeurs du Génie footpath (12), the GR1 goes off to the right. Take the opposite direction and carry straight on for about 250-300m before taking a sharp right onto a barely visible path with worn white waymarks, which separates forest plots 111 and 112. You will soon reach the edge of the plateau. The path goes down into a kind of ravine to reach the valley floor and the Chemin de la Vallée d’Arbonne, which you go straight over. You will reach the end of the Vallée d’Arbonne walk at the yellow waymark (1), which you began at a few hours earlier, and you can make your way back to Canche aux Merciers car park.

Waypoints

  1. S/E : km 0 - alt. 74 m - Parking de la Canche aux Merciers
  2. 1 : km 0.3 - alt. 76 m - Bifurcation
  3. 2 : km 2.37 - alt. 86 m - Crossing with the 25 moguls trail
  4. 3 : km 2.53 - alt. 78 m - Follow the 25 moguls trail
  5. 4 : km 3.28 - alt. 72 m - Crossing with Chemin de la Vallée Close
  6. 5 : km 4.34 - alt. 85 m - Leaving the 25-moguls trail
  7. 6 : km 5.11 - alt. 68 m - Crossing Chemin Plaine de Jean des Vignes
  8. 7 : km 5.86 - alt. 74 m - Junction at the end of the white sand sea - Bilboquet du Cul du Chien
  9. 8 : km 6.35 - alt. 70 m - Crossroads with the Ancien Chemin de Melun
  10. 9 : km 7.44 - alt. 72 m - Chemin de Melun au Vaudoué
  11. 10 : km 8.31 - alt. 110 m - Tortoise Rock
  12. 11 : km 8.97 - alt. 77 m - Junction with the GR1
  13. 12 : km 10.74 - alt. 111 m - Carrefour des Sapeurs du Génie (leave the GR1)
  14. S/E : km 11.93 - alt. 74 m - Parking de la Canche aux Merciers

Practical information

Departure and arrival: Canche aux Merciers car park

Difficulty: medium to hard (or athletic) because, during part of the walk, you will take the 25 Bosses (25 Bumps) footpath which is very rugged and has become a training ground for trail runners. Our route only takes you over 4 of the “bumps”, but the path is steep in places with difficult passages between the rocks. You will need to be careful and it is advisable to have very good shoes that grip your foot well and don’t slip. It should also be noted that for much of the walk you will be walking in sand.

Bring water with you (there is no water point on this route).

It is essential that you bring an IGN map 1/25000 as the area is wild and the paths are not always well marked. The forest plot numbers are also indicated in the walk information sheet to help you. A compass would be useful and won’t clutter your bag...

 Always stay careful and alert while following a route. Visorando and the author of this walk cannot be held responsible in the event of an accident during this route.

The GR® and PR® markings are the intellectual property of the Fédération Française de Randonnée Pédestre.

Reviews and comments

4.4 / 5
Based on 79 reviews

Reliability of the description
4.2 / 5
Clarity of route map
4.3 / 5
Route interest
4.7 / 5
patrick.bele
patrick.bele

Overall rating : 4.3 / 5

Date of walk : Jun 07, 2025
Reliability of the description : ★★★★☆ Good
Clarity of route map : ★★★★☆ Good
Route interest : ★★★★★ Very good
Busy trail : Yes

A very fine walk, quite busy in places.

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Mirna
Mirna

Overall rating : 5 / 5

Date of walk : Nov 11, 2024
Reliability of the description : ★★★★★ Very good
Clarity of route map : ★★★★★ Very good
Route interest : ★★★★★ Very good
Busy trail : Yes

A great hike, with a very nice location in the mythical Massif des Trois Pignons. Varied route, sand, rocks, paths, forests with beautiful autumn colours. One thing to avoid during the spring/summer season is the 25 moguls circuit, which is very busy.

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Fred_Mrss
Fred_Mrss

Overall rating : 4.7 / 5

Date of walk : Oct 30, 2024
Reliability of the description : ★★★★★ Very good
Clarity of route map : ★★★★☆ Good
Route interest : ★★★★★ Very good
Busy trail : No

It was a great outing lasting around 3.5 hours, with a lunch break on one of the 25 bumps on the route, which afforded a great view! We passed a few people on the bumps, but the start and finish of the route are less busy, more in the forest away from the busy areas. There were no particular difficulties, but you need to walk at a pace of 5/6 km to keep up with the pace. There are occasional misdirections along the route, with a few metres' difference in direction, which is quickly made up for when you keep an eye on the app A lovely walk that alternates between sandy paths, firmer paths, forest and moguls: I recommend it 👍

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Viapal91
Viapal91

Overall rating : 4.3 / 5

Date of walk : Aug 14, 2024
Reliability of the description : ★★★★☆ Good
Clarity of route map : ★★★★☆ Good
Route interest : ★★★★★ Very good
Busy trail : Yes

This wasa very nice walk, a bit sporty at the start with the first 4 bumps, but perfect. This walk gave us the opportunity to discover the Fontainebleau forest, which we had never seen before. A bit crowded when we crossed the 25-moguls circuit, but otherwise fairly quiet. The weather was very fine, so there were no problems with slipping on the rocks or on the slightly steep sections (hiking boots). I had no major problems finding my way around because I had the GPS app. The carrefour des sapeurs is no longer indicated by that name, but no worries about following the right direction. It's not easy to follow the description towards point 8. We didn't make the detour to the Rocher de la Tortue (Turtle Rock) towards the end of the route. Very nice route.

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Capucines26
Capucines26

Overall rating : 5 / 5

Date of walk : Aug 04, 2024
Reliability of the description : ★★★★★ Very good
Clarity of route map : ★★★★★ Very good
Route interest : ★★★★★ Very good
Busy trail : No

Leaving the car park, we followed a path just to the right that joins the red track a little further on for its shade and flowering heather. The rocks are slippery in the bumps because of the sand, so you have to be careful when going down the large masses. But it's a very nice walk in the Massif, bucolic and sporty at the same time!

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filoman
filoman

Overall rating : 4.3 / 5

Date of walk : Jun 30, 2024
Reliability of the description : ★★★★☆ Good
Clarity of route map : ★★★★☆ Good
Route interest : ★★★★★ Very good
Busy trail : Yes

A very fine circuit, fairly busy on the 25 bumps section and around the cul du chien sands. It's not difficult to find your way around, but use the GPS.

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ealet
ealet

Overall rating : 4 / 5

Date of walk : Jun 22, 2024
Reliability of the description : ★★★★☆ Good
Clarity of route map : ★★★★☆ Good
Route interest : ★★★★☆ Good
Busy trail : Yes

A fairly strenuous but very pleasant hike, to be avoided on Sundays as it is very busy in the part it shares with the 25 BOSSES circuit.
beautiful viewpoints
the gps came in handy at point 8 (didn't understand the description)
thank you to the author for sharing

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thierryP77
thierryP77

Overall rating : 4.7 / 5

Date of walk : Jun 09, 2024
Reliability of the description : ★★★★★ Very good
Clarity of route map : ★★★★★ Very good
Route interest : ★★★★☆ Good
Busy trail : No

nice circuit covering 4 bumps of the circuit of 25 bumps where there are indeed a few people but otherwise the rest of the course is quiet. pause on the sands of the cul du chien in the middle of the course for a break or a picnic, ideal. moreover the good weather was part. thank you for this course.

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ALCHOURROUN
ALCHOURROUN

Overall rating : 4.3 / 5

Date of walk : May 05, 2024
Reliability of the description : ★★★★☆ Good
Clarity of route map : ★★★★☆ Good
Route interest : ★★★★★ Very good
Busy trail : No

It was the first time I'd used the application. There was a discrepancy on my mobile phone between the position indicated by the app on the route and my actual position.
The route is varied and offers great views of the Fontainebleau forest. It's easy to do as a family with children over 10.

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FarMeb
FarMeb

Overall rating : 4.3 / 5

Date of walk : Dec 18, 2023
Reliability of the description : ★★★★★ Very good
Clarity of route map : ★★★☆☆ Average
Route interest : ★★★★★ Very good
Busy trail : Yes

The Forêt des 3 Pignons can't be described in words - it's a world in itself. Valleys, pools, sand, rocks sculpted by the wind, bumps... Not a forest... THE FOREST. It's a trip you have to make once in your life... and to those who are unhappy, what can I say but that you don't deserve it.

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La torpille
La torpille
• Last modified:

Overall rating : 3 / 5

Date of walk : Dec 09, 2023
Reliability of the description : N/A
Clarity of route map : N/A
Route interest : ★★★☆☆ Average
Busy trail : Yes

Not a great route, lots of cycling

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casto50
casto50

Overall rating : 4.7 / 5

Date of walk : Apr 09, 2023
Reliability of the description : ★★★★★ Very good
Clarity of route map : ★★★★★ Very good
Route interest : ★★★★☆ Good
Busy trail : Yes

Pleasant walk, thank you
Practical GPS for crossing the sands of the cul du chien

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KRIECHLAK
KRIECHLAK

Overall rating : 4.7 / 5

Date of walk : Sep 23, 2022
Reliability of the description : ★★★★★ Very good
Clarity of route map : ★★★★☆ Good
Route interest : ★★★★★ Very good
Busy trail : Yes

pity it was raining, slippery rocks, otherwise use of GPS useful

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Lucette 91
Lucette 91

Overall rating : 3.7 / 5

Date of walk : Aug 20, 2022
Reliability of the description : ★★★☆☆ Average
Clarity of route map : ★★★☆☆ Average
Route interest : ★★★★★ Very good
Busy trail : Yes

The first part of the route was easy to find, but then, after descending the Rocher du Guetteur, the directions were wrong (name of path, route indicated on the map, badly detailed shortcut, etc.). In short, we ended up on the GPS with a bump that wasn't on the programme and an extra 3 km on the clock. But it was beautiful! On the other hand, there was a lot of walking in the sand, which was more tiring than on hard ground. 4h30 of walking in total for 15 km.

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Olivier Martine
Olivier Martine

Overall rating : 2.7 / 5

Date of walk : May 22, 2022
Reliability of the description : ★★☆☆☆ Disappointing
Clarity of route map : ★★☆☆☆ Disappointing
Route interest : ★★★★☆ Good
Busy trail : Yes

The start of the route is well signposted, but from halfway onwards you can't find the paths described, and we had to use the GPS to find the car park again!

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