The region of the Valles Pasiegos encompasses the territorial ensemble of the river basins of the Pas, Pisueña, and Miera rivers. These are three valleys with similar conditions regarding the cultural and social characterization of the rural community that inhabits them, the same community that has been shaping its agricultural landscape over the past five centuries, during which one of the most peculiar anthropic landscapes of the entire Cantabrian mountain range has been formed. However, within this framework of sociocultural homogeneity, each valley has its unique idiosyncrasy, with distinctive features that set it apart from its neighbor and make it unique in the Pasiego context. The physical shaping of the territory or issues related to more recent economic development are at the base of these more local particularities. The term 'pasiego' is not simply the inhabitant of the Valles Pasiegos. This demonym originally defined a geographical issue (the Pas was the river of the “pass,” because at its headwaters, the Lelsa or Aguasal route allowed passage over the challenging orography of the mountain range when the snow cleared the passes during summer, connecting this rugged sector of Cantabria with the merindades of Castilla). Now, the term pasiego refers to a way of life, necessarily linked to livestock activities, to the challenging relationship between humans and the environment where they establish their activities, and to their ability to adapt to obtain the maximum yield from the scarce resources that nature has made available to them.