Asturias de Santillana is a historical comarca whose territory in large part corresponded to the central and western part of today's autonomous community of Cantabria, as well as the extreme east of Asturias.
Its borders used to go along the coast from the council of Ribadedeva to the municipality of El Astillero (old Camargo Valley), to the shores of the Bay of Santander), which leads to the administrative division of Trasmiera.
The merinos were representatives of the king and they lived in this administrative division of Santillana del Mar (Cantabria), which is the capital of that territory since 1209.
In 1581, soon after the Nine Valleys Lawsuit, the governor stopped being a marine major and became known as a "corrigador," a local administrative and judicial official.
Along the marine coast one finds the localities of Santillana del Mar, Comillas and San Vicente de la Barquera.