The first sign of the Cornón route is a stone marker at the entrance to Santa María del Puerto, “El Puertu” for the locals. There are also signs and good views of the Cantabrian mountains. The atmosphere is really suggestive to start a great mountain route. The PR-AS 10 trail leaves the town towards the west along the alleys of the great pastoral plain of the Puerto River, which rises on the Asturian side and curiously descends from the mountain range on the Leonese side to be the first tributary of the Sil River. The path is comfortable and pleasant between stone walls and plots of pasture, the landscape is so idyllic and pastoral that it seems created to be framed. The summit of Cornón is not in sight and can be confused with the energetic and challenging limestone silhouette of Peña Penouta and its sister Las Camposas, which close the horizon of the mountain range towards the Asturian side. Along the way there are several hills and small valleys that block the view from the large valley of meadows and hills of the Puerto valley.