Col du Portillon/Coll de Portilló is an international high mountain pass at an elevation of 1.293m (4,242ft) above the sea level, located in the Pyrenees, a mountain range on the border between France and Spain.
The road over the pass is asphalted. The speed limit is 40 km/h and the pass links Bagnères-de-Luchon in France and Bossòst in the Val d'Aran, Spain. The French/ Spanish border is situated on the summit of this col. The pass has been used by the Tour de France bicycle race.
There are 2 routes to reach the summit. On the French side, the road is called D618A. Starting from Bagnères de Luchon, the ascent is 10.2 km long. Over this distance, the elevation gain is 663 meters. The average percentage is 6.5 %. From Luchon the climb is longer and includes some steeper sections after about 3km in, but eases in the middle. This side is exposed to the sun and the natural rock face the road was cut from, can radiate a lot of heat as well.
On the Spanish side, the road is called N-141. Starting from Bossost, the ascent is 8.6 km long. Over this distance, the elevation gain is 583 meters. The average percentage is 6.8 %. The road has many bends.