The high plateaux of the Jura mountains (wjura-tourism.com) guarantee good snow cover in winter, but they also lack the steep gradients of the Alpine peaks further to the south; it is this high but level terrain which has made the Jura into France’s most popular destination for cross-country skiing, or ski de fond. The goal of any superfit fondeur is the 175km Grande Traversée du Jura (GTJ), which crosses the high plateau from Villers-le-Lac to Giron, a town in the south of the Parc Naturel Régional Haut Jura.
The same gentle topography and established infrastructure that enable cross-country skiing have made this region an ideal high-summer venue for mountain biking, with hundreds of waymarked cross-country skiing pistes used out of season as trails for adventurous mountain bikers. The 360km GTJ–VTT, which starts near Montbéliard (just to the south of Belfort), has become the greatest long-distance biking challenge in the area. Many people cycle on the road; there aren’t many cars, so if you can handle the hills, then go for it.