The river Valserine () is a tributary of the Rhône that flows for from the Col de la Faucille in the Jura Mountains to its confluence with the Rhône at Bellegarde-sur-Valserine. The Valserine Valley has great charm; it includes the Pont des Pierres that spans the river between Montanges and Mulaz (in the commune of Confort),Valserine, www.planetware.com. Accessed 31 March 2008 as well as the Pertes de la Valserine just north of Bellegarde-sur-Valserine, a canyon in which during the dry season the Valserine runs underground.
As the river flows through the village of Mijoux, it marks the border between Ain (a department in the Auvergne-Rhône-Alpes region) and Jura (in Bourgogne-Franche-Comté).Monts Jura, www.frenchaccommodation.co.uk Accessed 31 March 2008map
The name Valserine stems from a univerbation of val + serine, where val is an ellipsis (omission) of ruisseau de val (valley stream), and serine is likely a hydronym from a different river, from the alternate spelling serein, itself derived from Latin serēnus.
See also Frainc-Comtou dialect Parc naturel régional du Haut-Jura Jura Mountains
References
Further reading Parks, Reserves, and Other Protected Areas in France (Haut-Jura and Pont-des-Pierres) Natura 2000 : Fiche du site FR8201648 (GALERIE A CHAUVES-SOURIS DU PONT DES PIERRES) (French)