Valserine
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, 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 and Jura.
The name Valserine stems from a univerbation of val + serine, where val is an ellipsis of ruisseau de val, and serine is likely a hydronym from a different river, from the alternate spelling serein, itself derived from Latin serēnus.