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