The toughest day hike near Paris and one of the most fun: a loop over 25 rocky humps in the Trois Pignons massif, scrambling up sandstone boulders, sliding down sandy slopes and threading through pine and heather. It feels like a small mountain range an hour from Notre-Dame.
Fontainebleau forest is famous among climbers worldwide for its sandstone boulders. In its south-western corner, the Trois Pignons massif packs dozens of rocky ridges into a small area of sand, pine and heather.
The Circuit des 25 Bosses links 25 of those summits in one marked loop. None is higher than about 150 metres above the valley, but the path goes straight over each one, so the climbs never stop: more than 800 metres of up and down in all. You use your hands on the rocks, wade through soft sand in the dips and get views from every top across a sea of trees.
On the way you pass the Croix de Lorraine on a rocky crest, a memorial to the Resistance fighters who hid in these woods during the Second World War. It is a hard day: start early, carry plenty of water and expect sore legs.
The sandstone is grippy when dry and treacherous when wet. Several sections involve short scrambles with a drop below. Avoid it after rain, and turn back if you are not comfortable.
Follow the painted markings carefully: other circuits cross the massif in different colours.
Schematic: the real thing has less rhythm and more sand.
Most people start from one of the forest car parks on the edge of the massif near Noisy-sur-École or Le Vaudoué and join the loop wherever it passes. Pick a direction and stick with the same markings.
The first humps teach the pattern: a scramble up rounded boulders, a few minutes along a sandy crest with views, then a slide down into a pine-filled dip.
The middle section crosses the wildest ridges, with open heather moorland and the Resistance memorial on its rocky crest. Rest stops on the summits look out over the treetops.
The final bosses are where tired legs feel it most. Take care on the descents; most slips happen late in the day.
The trailheads are about an hour south of Paris near Noisy-sur-École and Le Vaudoué. Parking is free; arrive early at weekends.
Take the Transilien R from Gare de Lyon to Fontainebleau-Avon or Bois-le-Roi (about 40 minutes) and take a taxi to the Trois Pignons, or walk the boulder circuits that start near those stations instead.
No fires, stay on paths in protected areas and take your rubbish home. In summer, check fire-risk restrictions before you go.
Paris practical notes →Wikimedia Commons photographs are used under their licences; Pexels photographs under the Pexels licence.
