The Forest of Fontainebleau - Les circuit des 25 bosses

This guide takes the shape of me simply sharing my weekend adventure / challenge, and letting it serve as inspiration, or not, for your own expedition.

The challenge? To hike Les circuit des 25 bosses without using a car to get there. It's a bit risky, but I like that element of danger and trouble to keep everything on its edge.

So what is Les circuit des 25 bosses? Well it's one of the more interesting and rewarding hiking trails in the forest of Fontainebleau. It's name roughly translates to 25 bumps, so as you can imagine, it involves hiking up and down at least 25 times.

It's the perfect place to see the large boulders for which the forest is known. The catch is that it's on the western edge of the forest, about as far away as you can get from the normal train access point. As a result, normal access is by car. And hence my challenge...

Canola fields forever

Step 1 - Take the RER D to Buno-Gironville (D4 line) in the early hours of the morning. The 8:30 train from Gare de Lyon had me arriving at Buno around 10:00 am.

Step 2 - Walk for approx. 3hrs (11km) from the Buno station to Fontainebleau forest. The walk is generally flat and follows small country roads and short cuts through farm fields. You can refer to my GPS route map for an idea, but it's important to note that there is no completely direct path, and that the paths through farm fields change with the seasons. In fact my inspiration came from a French girl who claimed she covered the distance in 2hrs (I'm suspicious of course, in true macho style).

Step 3 - The best step. The hike itself. The start of the trail is served by a large car park...ideal to get your initial bearings. From there the trail is well marked with red markers, and takes 5-6hrs (16km) with a total climb of 830m. Taking a clockwise direction will have you finishing with the easier section. The 'bumps' cover the wide variety of vegetation and terrain that Fontainebleau has to offer, so well worth the effort. Some of the 'bumps' involve some minor climbing, however scrambling up and down rocks every so often is half the fun. In all cases, the climbing can be avoided by taking an alternative path.

Step 4 - The walk back. Another 3 hrs (11 km) to Buno train station for the last train. For me it was 8:30 pm but you'll want to check this of course.

Step 5 - Train back to Paris from Buno.

And in case you had noticed, yes indeed, my numbers don't add up. The reason being that I ran out of time and cut the circuit short to get back in time. A wise recommendation if you don't want to spend your night on a cold empty train platform!

In conclusion, I'm not sure I would recommend my approach to anyone! 38km and up to 12hrs of hiking is a big task for even the most experienced hiker.

Given the highlight is Les circuit des 25 bosses, I recommend hiring a car or taking your bike on the train to get there. You'll cover the 11 km from Buno quicker by bike, and the trains allow bikes in some carriages.

And of course taking a car makes it easier again. Note that there are alternative entry points if you go by car, so you'll have a few options.

Other points:

••  There are several alternative trails that are shorter / longer / easier / more difficult depending on your preference.

••  I recommend side trails to 'Les Sables du Cul de Chien', an open stretch of sand surrounded by the forest; and 'la Diplodocus', a nose shaped boulder located in one of the popular bouldering sites.

••  It's always wise to have a map. IGN 2417OT - Foret De Fontainebleau.

Obligatory disclaimer: As with all big hikes, you need to take the appropriate precautions and make the usual preparations. And if you don't know what I'm talking about then you shouldn't attempt the hike. It should also be noted that the train mentioned above is not the normal way to reach Fontainebleau. The normally visited part of Fontainebleau forest is accessed via a completely different line (an SNCF line).