Col de Castillon is a mountain pass at an elevation of 707m (2,319ft) above the sea level, located in the Maritime Alpes, in France. The pass is traversed by the scenic Route des Grandes Alpes.
The road to the summit is asphalted. It’s called D54 and includes several narrow and steep sections. In many places the road is bordered by a drop of hundreds of meters (many hundreds of feet) unprotected by guardrails. Near the summit there are some military fortresses from WWII. It is easily bypassed by a newer main road, which stays in the valley and goes through a tunnel. The pass has therefore very little traffic until the two roads converge above Menton. The name Castillon derives from a village located just to the west of the pass. It was destroyed by an earthquake in 1877.
The pass has been climbed by the Tour de France race. There are 2 routes to reach the summit. Starting from Sospel, the ascent is 7 km long. Over this distance, the elevation gain is 359 meters. The average percentage is 5.1 %. And starting from Menton, the ascent is 15 km long. Over this distance, the elevation gain is 697 meters. The average percentage is 4.6 %.