From Chamaloc, on the edge of Die, the Col de Rousset opens the way into the Vercors massif via a steady 9.3 km climb averaging 5.7%, capped by a tunnel that bores through the final rocky barrier before the plateau.
A gradual climb to the plateau
The road climbs in broad hairpins through a landscape that gradually shifts from the vineyards of the Diois to the alpine pastures of the Vercors, at a steady gradient that only rarely exceeds 8%. The final kilometre plunges into a lit tunnel that bypasses the old route, now closed due to avalanche exposure.
A historic gateway to the Vercors
The Col de Rousset traditionally marks the boundary between the Diois and the Vercors plateau, a region shaped by its role in the French Resistance during the Second World War, notably around Vassieux-en-Vercors. The contrast between the Provençal climate on the southern side and the mountain feel of the plateau is felt as soon as you emerge from the tunnel.
Getting the climb right
A front light is useful for crossing the tunnel safely, while a windbreaker jacket is worth having for the descent on the plateau side, often cooler than the Diois slope.
When to go
April to October — the tunnel generally stays open longer through the year than the old open-air route it replaced.
Good to know
Die, known for its Clairette sparkling wine and Provençal market, makes an ideal base for combining the Col de Rousset with exploring the Diois vineyards and other Vercors roads.
