It is first attested asmons Iura in book one ofJulius Caesar'sCommentarii de Bello Gallico.Strabo uses a Greek masculine formὁ Ἰόρας ("through the Jura mountains",διὰ τοῦ Ἰόρα ὄρους) in hisGeographica (4.6.11). Based on suggestions byFerdinand de Saussure, earlycelticists such asGeorges Dottin tried to establish an etymon "iura-, iuri" as a Celtic word for mountains,[2] with similar putative etymologies (e.g. *juris, "mountainous forest") still appearing in more recent non-academic publications.[3] However, since there are no clear cognates in the surviving corpus of the Celtic languages, modern studies of Proto-Celtic and Gaulish etymology tend not to list anylemmata connected to Jura, and the name must be considered fundamentally unclear.[4]
The Jura Mountains are a far province of the largerCentral European uplands. The Jura range proper lies inFrance and Switzerland.[5]
In France, the Jura covers most of theFranche-Comté region, stretching south into theRhône-Alpes region and north into theGrand Est region. The range reaches its highest point at theCrêt de la Neige (1,720 m (5,640 ft)), in department ofAin, 5 km west from the Swiss border of thecanton of Geneva, and finds its southern terminus in the northwestern part of thedepartment ofSavoie. The north end of the Jura extends into the southern tip ofAlsace (Sundgau). Roughly 1,600 km2 (600 sq mi) of the mountain range in France is protected by theJura Mountains Regional Natural Park.
Topographical map (relief map) of Switzerland showing the Jura range proper (Faltenjura) in the northwest and west, and theAlps in the south and east
The Swiss Jura is one of the three distinct geographical regions of Switzerland, the others being theSwiss plateau and theSwiss Alps. Most of the range covers the western border with France. In Switzerland, the Jura Mountains extend over an area covering (from northeast to southwest) thecantons ofZurich,Aargau,Basel-Landschaft,Solothurn,Jura,Bern (i.e.,Bernese Jura),Neuchâtel,Vaud, andGeneva. The easternmost mountain of the Jura range proper is theLägern, situated east of the river Aare. Much of the Swiss Jura region has no historical association withEarly Modern Switzerland and was incorporated as part of the Swiss Confederacy only in the 19th century. In the 20th century, a movement forJura separatism developed, which resulted in the creation of the Canton of Jura in 1979.
The east of the Jura range properseparates theRhine andRhônebasins. The northern and eastern part of the range drains towards the Rhine river and its tributariesAare andIll, whereas the western and southern parts drain towards the Rhône river and its (sub)tributariesDoubs,Saône, andAin. Initially the river Doubs (a subtributary of the Rhône) flows about 100 km (62 mi) northeast, briefly venturing into Switzerland, then changing direction and flowing about 170 km (110 mi) southwest before joining the Saône ca. 140 km (87 mi) north of the French city ofLyon. In Lyon, the Saône joins the Rhône. While the Rhine flows into theNorth Sea, the Rhône flows into theMediterranean Sea.
The range is built up vertically while decreasing in size laterally (along a rough northwest–southeast line). This deformation accommodates the compression from alpine folding as the mainAlpine orogenic front moves roughly northwards. The deformation becomes less pervasive away from the younger, more active Alpine mountain building.
The geologic folds comprise three major bands (lithological units) of building that date from threeepochs: the Lias (Early Jurassic), the Dogger (Middle Jurassic) and the Malm (Late Jurassic)geologic periods. Each era of folding reveals effects of previously shallow marine environments as evidenced by beds withcarbonate sequences, containing abundantbioclasts andoolitic divisions between layers (called horizons).
Structurally, the Jura consists of a sequence of geologic folds, the formation of which is facilitated by anevaporiticdecollement layer. The box folds are still relatively young, which is evident by the general shape of thelandscape showing that they have not existed long enough to experienceerosion, thus revealing recent mountain building.
The Jura range offer a variety of tourist activities including hiking, cycling, downhill skiing and cross-country skiing. There are many signposted trails including theJura ridgeway, a 310 km (190 mi) hiking route. Several peaks featureobservation towers (e.g.Faux d'Enson,Hage).
Tourist attractions in the Swiss Jura include natural features such as theCreux du Van, lookout peaks such as theChasseral, caves such as theGrottes de Vallorbe, as well asgorges such asTaubenloch. The Swiss Jura has been industrialized since the 18th century and became a major centre of thewatchmaking industry. The area has several cities at very high altitudes, such asLa Chaux-de-Fonds,Le Locle andSainte-Croix (renowned for itsmusical boxes); however, it generally has had a marked decline in population since 1960. Both Le Locle and its geographical twin town La Chaux-de-Fonds are recognised as an UNESCOWorld Heritage Site for theirhorological and related cultural past.
In the French Jura, the 11th-centuryFort de Joux, famously remodeled and strengthened byVauban in 1690 and subsequently by other military engineers, is situated on a natural rock outcropping in the middle of the range not far fromPontarlier. Part of theA40 autoroute crosses through a portion of the southern Jura betweenBourg-en-Bresse andBellegarde-sur-Valserine, which is known as the "Highway of the Titans".
