The Haut-Jura, famous in winter for its nordic ski area, turns into generous mountain bike terrain in summer: dense fir forests, open alpine pasture, and a trail network partly inherited from cross-country ski trails repurposed for the summer season.
Terrain between dense forest and open pasture
Starting from Les Rousses, a resort on the lake of the same name, the route heads into the forest of the Jura massif before opening onto the pastures of the Haute Chaîne, with clear views over Lake Geneva and the Alps on a clear day — a striking contrast with the dense tree cover of the first part.
A representative day loop: around 40 km and 750 m of elevation gain between Les Rousses, Prémanon and the Haute Chaîne area, on terrain that alternates wide, fast-rolling tracks with more technical singletrack through the woods.
How to approach the ride
The Jura is a distinctive limestone range: terrain can be slick on exposed rocky areas, especially after rain, which is frequent in this border range. A versatile tire, neither too smooth nor too aggressive, suits the variety of terrain you’ll encounter.
MTB trail marking is generally good on the official routes linking the resorts, but some wilder forest trails are worth backing up with a GPX track.
When to go
The usable season runs from June to September, with peak conditions in July-August when trails are driest. Spring is often still too wet due to the late snowmelt typical of this mid-altitude but heavily-watered range.
Good to know
Les Rousses has MTB rental shops (including e-MTBs) used to the resort’s four-season clientele, along with a wide choice of accommodation carried over from its winter business.