The valley of Valserine is located in the massive of the Jura, Département of Ain. It is parallel to highest peaks the. It was formed by the Valserine , a torrent of the Regional Park of the High Jura which joins Semine.

The valley starts from Mijoux (1000 m of altitude) and goes down towards the south until Bellegarde-on-Valserine (350 m) while forming a valley with on the right-sided the solid mass from Lajoux and, on the left side, the High Jura with the Crêt of Snow (1720 m).

The climate is cold in winter with abundant snowfalls especially on the side of Mijoux and Lelex and enough heat in summer, even very hot with Bellegarde-on-Valserine.