The Puerto de Casillas is a mountain pass and natural viewpoint located at an altitude of 1,470 m, in the municipality of Casillas, at the eastern end of the Sierra de Gredos. Its interest does not lie in a built platform, but in the cut of the relief itself: a pass between pine forests that opens the view towards the Iruelas Valley, the reservoir of El Burguillo and, on clear days, towards the Sierra de la Paramera and other surrounding reliefs. From the high point it is easy to understand its function as a natural corridor between the Tiétar valley, the Iruelas valley and the Alberche basin. It is also the natural entrance to the Natural Reserve of the Iruelas Valley, a protected area for its forest and wildlife value, with an outstanding presence of black vultures. The area is also mentioned in local and hiking guides as an access to Pozo de la Nieve and Alto del Mirlo. The visit experience combines mid-mountain scenery, masses of pine trees and wide panoramic views over hillsides and reservoirs. It is not an urban or conditioned viewpoint, but a road stop with clear territorial reading: relief, forests and water in a single glance. The best time is usually spring and autumn, when the light is cleaner and the colors of the mountain and valley are more intense. In winter there may be cold, fog or ice on the ascent, and in summer the haze reduces visibility.
