The beauty of the Jura region lies in the 300km-long arc of limestone hills along the border between France and Switzerland, the western flank of which creases into a series of spectacular valleys and gorges enlivened with waterfalls and dotted with medieval towns and villages. A rich forest populated by lynx, boar and deer covers almost half the region, which is also known as the Franche-Comté.
Where there is limestone, there are likely to be caves, and the Jura has over 4,000 of them, including some of France's most spectacular warrens of passages, occasionally punctured by cathedral-like chambers. Near Arbois is the Grotte des Planches (00 33 3 84 66 13 74; grotte-des-planches.net) where the River Cuisance flows underground, creating stalactites and giant pot-holes. Open 10am-5pm from mid-March to November; admission €7.50.
Many of these caves have only been opened to visitors since the Second World War, but Les Grottes d'Osselle (00 33 3 81 63 62 09; grottes.osselle. free.fr) was visited centuries before. Situated in a cliff overhanging the River Doubs, around 20km south-west of Besançon, the caves include a bridge built in 1751 over an underground river. Open daily from April-October; admission €7.
The quiet, winding roads and impressive stretches of wilderness make the region a magnet for walkers, mountain and touring bikers, canoeists and cross-country skiers. The best-known long-distance route is the Grande Traversées du Jura, which can be tackled on foot, horse, bike or skis. Most people head south, starting in Mandeure in the Doubs département and passing through some spectacular scenery over the 400km distance to Culoz in Ain.
To organise your own route and accomodation, visit across-jura.com. Alternatively, Inntravel (01653 617000; inntravel.co.uk) offers a seven-day "Lake Geneva to Lake Neuchâtel" walk between La Cure and Les Rasses, in Switzerland. The trip starts at £778 per person including all meals. Hooked on Walking (01501 740985; walking-europe.co.uk) offers a seven-night tour starting in Arbois and finishing in Lons-le-Saunier from £744 per person, including breakfasts and two dinners.
For mountain bikers, there are 120 marked circuits, with information boards at key points. Saddle Skedaddle (0191 265 1110; biking.skedaddle. co.uk) offers a seven-day guided exploration, taking in pine forests and open pastures. The trip costs £890 (bike hire an extra £140), including most meals.
Too energetic? Sit back on one of Europe's most curious railway lines. The Ligne des Hirondelles ("Swallow Line") between Dole, Morez and St-Claude is a 123km-long journey that takes two and a quarter hours. It's easy to see why it took 50 years to complete: 36 tunnels and 18 viaducts mark the route.
Though the region attracts visitors looking for outdoor pursuits, it also has rich historical associations. Gustave Courbet (1819–77), leading light of the French realist school, was born in Ornans and the house where he was born is a museum (00 33 3 81 25 81 25; musee-courbet.doubs.fr) with 50 of his works on display. It reopens after renovation on 2 July. Open daily; admission €6.
Bacteriologist Louis Pasteur (1822–95) was born in Dole, where his birthplace is a museum (00 33 3 84 72 20 61; musee-pasteur.com). Open daily; admission €5.
Take to the water
The region is dotted with lakes and threaded by some of France's most scenic rivers, with impressive gorges and spectacular waterfalls. Fishing is particularly popular on the Loue, Doubs and Dessoubre rivers, and canoeists favour the Loue for the stretch between Vuillafans and Cleron, which has 10km of calm water ideal for families and 10km of whiter stuff for thrill seekers. Riverboat tours are operated from Villers-le-Lac on the Doubs, taking visitors to see the 27-metre waterfall of Saut du Doubs.
The Rhône-Rhine Canal through Besançon and the rivers that flow from the Jura are excellent for boat cruising. Le Boat (0844 463 3594; leboat.co.uk) offers four-berth boats from Gray on the River Saône for a seven-day 200km cruise to the limit of navigation at Corre and back from £995. The route passes medieval and Renaissance villages, and passes through a 700-metre tunnel at one stage. The major waterway junction of St Jean-de-Losne is one of the bases for Cruise France (01756 706516; cruisefrance.com), the others being the market town of Fontenoy-le-Château and the former inland port of Gray. Seven-nights' hire of a two- to four-berth boat starts at £790.
Traditional meat-smoking is widely practised here in pyramidal-roofed buildings called tuyé. Smoked pork is used to make Morteau sausages (left); garlic and cumin are added to top-class pork to produce Montbéliard sausages. Trout, pike-perch and crayfish are common on menus. The Jura makes two of France's best-known cheeses: Comté and Morbier.
Two white and three red grape varieties go into the region's wines, the most distinctive being the vin jaune (yellow wine) of Château-Chalon, which matures in oak casks for 75 months. The region's signature dish is chicken in vin jaune with mushrooms.
The French Jura version of fondue requires Comté cheese, white wine and kirsch, one of the spirits produced at Fougerolles.
The salt of the earth
Salt production has bequeathed the region one of Europe's most extraordinary architectural curiosities. Arc-et-Senans (00 33 3 81 54 45 00; salineroyale.com) is a short walk from the station of the same name, on the line between Besançon and Bourg-en-Bresse.
Now a World Heritage Site, the semicircular royal saltworks complex was begun in 1775 on the orders of Louis XV. Production ceased in 1895 but the 11 buildings now form a museum devoted to the work of their utopian architect Claude-Nicolas Ledoux, as well as temporary exhibitions. You can even stay the night: double rooms are available for €172 including breakfast. Open daily; admission €7.50.
In nearby Salins-les-Bains, a museum (00 33 3 84 73 10 92; salinesde salins.com) occupies the site of a saltworks that closed in 1962. It provides a very different experience, with guided tours of the long stone-vaulted tunnels. Open daily; English language tours at 12.15pm and 2.15pm in July and August; admission €6.