According to official French definitions, a col is a mountain pass. It is the highest part of a road, in between two higher mountaintops. However, not all climbs in this tour are cols, and not all cols are climbs. Of the 108 named cols only some 70 are indicated as climbs.
Other climbs, that cannot be characterized as "cols" are called "côtes", which simply means "slope". There are 106 hills characterized as côtes. Most of them are small ones, but some of them are quite difficult, like the Côte de Ste Croix in the Cevennes, or the Côte de la Croix Signy, which is the longest climb in the Beaulolais.
A very remarkable col is the Col de Fourques in the Cevennes. You get there by descending the Mt. Aigoual. The Col is then the lowest point, after this the road goes up again to the Col de Perjuret. How comes that the lowest part of the road is called a Col? Simply: the col is located at a crossing, and the Col definition refers to the side roads, which both descend from the col.
108 classified cols
The route passes 108 classified cols. A col is classified if it is really the highest point of a road, or it is a high point where you leave the road to climb to an even higher col. Examples are the Col du Lautaret (where you take the branch to the Col du Galibier), or the Col du Caougnous where you take left to the Col de Peguere).
Moreover a classified col has to meet one of the following criteria:
• The col is included in the Chauvot (the list of all 8500 French cols);
• There is a name sign on top;
• The col is shown on Google Maps, the map Michelin, the IGN-map or a local map.
For colhunters we mention all unclassified cols too, but they are not part of the hundred. The route includes 54 unclassified cols. They are unclassified because it is not the highest point. It is nevertheless a col, because they have a name and they are the highest point for crossroads, like the Col du Wetstein (in the descent of the Col du Linge) or the Col de la Cravate (in the ascent of the Col du Minier).