The CUATRO VALLES Association is composed of twenty-six municipalities in the León Province (sub-regions of Laciana – Alto Sil, Babia, Luna, Omaña, Alto Torío, Alto Bernesga, and La Cepeda), with a total of 301 population centres, which covers 20% of the surface of the León Province (2,300 km²) and 20% of the province’s rural population (37,964 inhabitants)..

The municipalities: Los Barrios de Luna, Cabrillanes, Carrocera, Cármenes, Cuadros, Garrafe de Torío, Magaz de Cepeda, Matallana de Torío, Murias de Paredes, Las Omañas, Palacios del Sil, La Pola de Gordón, Quintana del Castillo, Riello, Rioseco de Tapia, La Robla, San Emiliano, Santa María de Ordás, Sena de Luna, Soto y Amío, Valdesamario, Vegacervera, Villablino, Villagatón, Villamanín, and Villamejil.