 Naranjo de Bulnes is part of the Cabrales region of Asturias, and lies within the Picos de Europa National Park.The first written reference to "Picu Urriellu" as "Naranjo de Bulnes" is credited to the German geologist and engineer, Wilhelm Schulz, who, in 1855, published the first topographic and geological map of Asturias.As far as is known the etymology of this name is not clear, because, historically, the local inhabitants always referred to the mountain as "Picu Urriellu".