Jocou, Mountain summit on the Isère–Drôme border, France

Jocou is a 2,051-metre summit on the border of the Isère and Drôme departments, at the junction of Lalley, Glandage and Lus-la-Croix-Haute. It is the highest point of the Diois pre-Alpine massif, overlooking the Haut-Diois to the west. Its southern ridge runs to the Col de Grimone, and the mountain forms a wind-funnelling corridor with the Rognon opposite, evidenced by the Col de Ventecul on its southern ridge.

In the mid-1970s the commune of Lalley built a ski area at 1,364 m on the mountain's slopes, with three ski lifts and a day shelter housing a rental shop. The main lift climbed south to the Col du Salut at 1,637 m and served two north-facing runs. Pines, firs and spruces were planted against avalanches above the buildings and the runs. Poor and irregular snow closed it in the early 1980s; the lifts were dismantled in two stages, the last pylon at the Col du Salut standing until the early 21st century. Remains today are the concrete cabin at the lift foot, the bases of several pylons and the plantations.

The mountain appears in Jean Giono's novel Un roi sans divertissement under the name "Le Jocond", where a bloodstained trail leads up its slopes; Giono names it again in L'Iris de Suse. The critic Jean Arrouye reads the name as the mount of Joconditas, of joy and rediscovered happiness. The current name Jocou replaced the older Jocon on the initiative of Lalley's mayor Gilbert Pelloux when the ski resort was created.

The ascent from the former ski station at 1,364 m climbs just under 700 m to the Crête de l'Archat and then the summit, on a steep pasture slope; the ridge passage is exposed. Allow two to three hours up and one to two down. From the Col de Grimone, start at the 1,294 m road bend by the Vallon de la Pouyat and head north-northeast via the Col de Vente-Cul and Col Pigeon.

The summit lies at the meeting point of three communes: Lalley, Glandage and Lus-la-Croix-Haute. Jean Giono calls it "Le Jocond" in Un roi sans divertissement and L'Iris de Suse, and Jean Arrouye reads the name as the mount of Joconditas, of joy.