Mont Joigny, Mountain summit in Chartreuse Mountains, France

Mont Joigny is a limestone summit in the Chartreuse Mountains of Savoie, reaching 1,556 m (1,558 m in some sources) west of the Col du Granier. It lies on the ridge between Apremont and Entremont-le-Vieux, where forested lower slopes give way to a band of pale rock along the upper ridge, with the highest point toward the left and a steep cliff dropping on the right.

This mountain forms part of the Chartreuse range, shaped over millions of years through geological processes involving limestone deposits and tectonic activity. The range has been a natural boundary and landmark in the Alps for as long as human settlement exists in the region.

The mountain's name appears in the local Savoyard form "Mont de Joigny". The ridge from the Col du Granier to the Col du Mollard closes the Entremonts valley on its northern side, and the valley's ravines drain the slopes below the summit. The protected zone covering the summit and ridges spans 548 hectares.

Hikers need proper footwear and equipment to navigate the rocky terrain and steep sections safely. Weather can change rapidly at this elevation, so checking conditions before heading out and bringing layers is important for a safe outing.

From the summit on clear days, you can see across the surrounding peaks toward the Col du Granier and the valley below in the distance. Many visitors overlook this panorama while focused on the effort of reaching the top.