Castrillón is a municipality in Asturias, located on the central coast of Spain. It has an area of 56.70 km2 and had a population of 22,361 inhabitants (in 2005). The most important population centres are the capital Piedrasblancas, Salinas, and Raíces. Asturias Airport is located in Castrillón. The airport is located in Anzu, parish of Santiagu'l Monte, municipality of Castrillón, 15 km from Avilés, 40 km from Gijón and 47 km from the regional capital, Oviedo.