Le Rocher d'Avon, Le Petit Mont Chauvet and Le Rocher de Bouligny

Starting point and access: Thomery station.
- Transilien - Line R, on the section between Paris-Lyon and Montargis.
Take the exit on the side of track 2, the one going from Montargis to Paris (if arriving in the opposite direction, track 1, take the underground passage).

Green and white markings

(S/E) With your back to the station, follow the path straight ahead, heading south. At the crossroads, take the^second path on the right, the Route du Rocher d'Avon. Continue straight ahead until you reach the Carrefour de la Croix de Montmorin crossroads.

No markings

(1) Go around the roundabout, either on the left (crossing the D606 and then the D301) or on the right (crossing the D301 and then the D606), and follow Route du Rocher d'Avon westwards again. At the next crossroads, go straight ahead.

(2) At the Carrefour des Sentiers d'Avon, continue straight ahead. At the next crossroads, take the^second road on the right, which is rather inconspicuous, the Route de l'Alouette. Wind your way through the ferns and note a few small rocks. Then cross the Route de la Mare des Pressoirs and continue straight ahead (north-west).

(3) At the next junction, turn left onto Route de Cheyssac. At the next junction, go straight ahead.

(4) At the next junction (metal gate on the right), turn left onto Route de la Percée, which is a steep uphill path.

Blue markings + blue capital letters on some rocks (see recommendations in the practical information section).

(5) Before the end of the hill, at a slightly marked junction, turn left onto a narrow path (be careful to spot this discreet start). Soon turn right, climb and pass at the foot of a vertical rock block topped by a "hat". Continue climbing, winding your way up. At a flat section, turn left, descend and then climb again to reach a viewpoint overlooking the forest.

(6) Then turn right and descend slightly. Zigzag between the boulders and then descend. At a rock with an engraving (evoking the damage caused by frost during the winter of 1879-1880), turn right and continue descending in a zigzag pattern. You will come to a path; follow it to the right and climb slightly. At a sort of pass, leave the path and take a trail on the right. Further on, rejoin the path you left earlier, follow it to the right and descend gently.

(7) Cross the Route de Poitiers and continue straight on along the Route de l'Écureuil. Soon leave the path for a trail on the right. At the start of a path, turn right and climb. Zigzag between the boulders, pass rock G and descend with bends. Wind your way through the pine forest among the ferns and heather. At a T-junction, go left.

(8) Cross Route d'Estrées and continue along Route de l'Écureuil. Further on, go around rock D on the right (the letter is written twice, on two different sides). Pass at the foot of a hill on the left and reach the Grotte de la Biche Blanche (marked with the letter C). Continue along the path and pass rocks B and A.

(9) At a three-way junction, turn right onto trail no. 10. At the next junction, go straight ahead.

No markings

At the crossroads, take the^third path on the left (west-southwest), the Route de Cheyssac.

Blue markings

At the next junction, turn left onto Avenue de Maintenon. Continue straight ahead, cross the D58 and walk alongside a car park.

No markings

After a forest barrier, continue straight ahead (ignore the blue markings on the right).

Yellow markings

(10) At Carrefour Lemonnier, at the foot of Petit Mont Chauvet, there are two options:
- Continue straight ahead and climb the steep slope of Petit Mont Chauvet.
- As shown on the map, take the^third left, the Route Tournante du Petit Mont Chauvet. Climb gently and steadily on this good, stable path. After a wide curve to the right, continue on fairly flat ground to the Carrefour du Mail d'Henri IV (on the right, there is a viewpoint overlooking Fontainebleau and its château).

No markings

(11) Turn left, heading south, and descend steeply over rocky terrain. At the bottom, at a crossroads, turn right (west) and follow the nature reserve on your right. Note a large building on the left, through the branches.

Blue markings + blue capital letters on some rocks (see recommendations in the practical information section)

(12) At the crossroads, take the^second path on the left, the blue path no. 9E (9 East). After a flat start, climb up a series of short hairpin bends. Pass under rock C (keep your head down). After the^second C marking (on the opposite side of the rock), turn right (be careful not to miss this fork). The path winds through the ferns. Pass between two boulders and you will come to a signpost for the blue trails.

(13) Then turn left towards Rocher de Bouligny. Walk on fairly flat ground through the ferns. Pass under rock G (keep your head down) and ignore a vague start on the left.

(14) At a crossroads, continue straight ahead along the Route du Rocher de Bouligny and climb uphill. Walk along a ridge dotted with rocks. At rock K, take a sharp left turn and stay on high ground. At rock M, veer right and leave rock N on your right. Then leave Mare Lebaudy on your right. Cross Route du Mail Henri IV on the left and continue on Route du Rocher de Bouligny (plateau landscape).

(15) At a fork, follow the blue double-headed arrow to the right to quickly reach the Rocher de Bouligny viewpoint (rock O). Retrace your steps.

(15) Back at the viewpoint, follow the blue trail to the right and down a steep descent.

No markings

At the crossroads, follow the Route de la Fanfare to the left and descend more gently.

(16) At the crossroads, turn right (east) onto Route d'Occident. Cross Route de la Palette. Then cross a small road and continue straight ahead on Route d'Orient.

(17) Cross the D148 and continue on the path opposite. Go straight ahead (east-northeast) and cross the Route de la Percée, the Route des Placereaux and the Route de la Croix du Grand Maître in succession. At the Carrefour de la Mare d'Épisy, take the^third left, still on the Route d'Orient. Leave the Mare d'Épisy on your right and continue straight ahead to the Carrefour des Sentiers d'Avon junction you took on the way there.

(2) Then take the^4th right, heading due east, onto Route du Rocher d'Avon. You will arrive at the Carrefour de la Croix de Montmorin junction, which you can go around on the left or right.

Green and white markings

(1) Continue east on Route du Rocher d'Avon. At the next crossroads, turn left at a 90° angle and follow Route des Fraillons north. Continue straight ahead to Thomery station (S/E).

To return home:
- Transilien - Line R, towards Melun and Paris-Lyon (direct access) or Montargis (take the underground passage).

Train timetables: consult the Transilien website.

For motorists:
Park in the Thomery station car park, located on the side of track 1.

Hiking boots are required.

No water sources identified along the route. The Rocher de Bouligny viewpoint (15) is a good place to stop.

Warning:
The Petit Mont Chauvet area is a managed biological reserve: do not stray from the paths, do not enter the undergrowth, keep your dog on a leash.

A 1:25,000 map is essential (at least the one accompanying this description). We recommend tracking the route on your smartphone using the Visorando app, especially on the Blue trails from (5) to (9) and from (12) to (16).

Recommendations for Blue-marked trails:
- The Denecourt-Colinet trails, marked in blue, mostly follow paths that wind through rocks and vegetation. It is impossible to describe all their twists and turns in detail.
- Despite the density of the markings and their maintenance (thanks to the markers!), it is recommended that you pay attention so as not to lose your way. If you have not seen a marker for some time, do not hesitate to retrace your steps until you find the markings again.
- Markers can be found on three types of supports, at three different heights: (i) on tree trunks at eye level; (ii) on rocks, at the same height or lower; on rocks protruding from the ground.
- A good sense of direction is generally required.
- On this hike, the section between (12) and (13) is particularly easy to get lost on. Stay on the marked trail and do not take the tracks on the left, which may be a shortcut to the southern branch, or may even take you back to the northern branch.

Hike completed by the author on 4 September 2022.

- Pleasant forest path and beautiful undergrowth of ferns and heather.
- Rocky chaos from (5) to (9) and from (12) to (16).
- Extensive views at (6), (11) and (15).