Tollbooth of Morgex. You continue towards Courmayeur, but before entering the town, you immediately take the intersection to the left for Arpy and the colle San Carlo. You continue until you reach the colle San Carlo. On the opposite side of the street, to the left, there is a parking area.

The itinerary was previously divided into two parts. The first part consisted in a nice stroll amongst the woods from the colle San Carlo to d’Arpy lake. The second part was an easy equipped trail towards the splendid lake of Pietra-Rossa. The path was clearly simplified and is still continuously pretty simple. It is an excellent ascent amongst waterfalls with rocky steps in the more difficult parts.

From the parking area you reach a clearly marked dirt road located near the fountain. Follow this rut towards the left, marked by yellow signs (trail marker 15). The road goes up in the woods where there are also some larch trees. You then reach a fork in the road. Go to the left (yellow trail marker and wooden sign). Continue until you come to another fork in the road. The dirt road continues along the hillside with benches placed here and there. You then reach a beautiful fountain and, after another small ramp towards the left, you reach d’Arpy lake.
You continue on the path on the right side (hydrographic left) reaching another little lake, an uptake of the first one. You continue on a smooth trail to the left that becomes steeper with every step (leaving the faraway dirt road to the right) coasting a rocky bar to the left. You reach a detrital clearing to the left of the d’Arpy river and continue towards various waterfalls, encountering the trail markers on the rocks (15, 19). Therefore you continue on trail marked steps that take to the first level and continue towards the right, then again onto steep ground, recently made with rocky steps and in some parts with very old metal material. The descent is smooth from the slope.