The Chartreuse Mountains (French: massif de la Chartreuse, French: [ʃaʁ.tʁøːz]) is a mountain range in eastern France, stretching to the north from the city of Grenoble to the Lac du Bourget. It is the southernmost range in the Jura Mountains and belongs to the French Prealps. The most important city in the Chartreuse Mountains is Voiron (Isère).