Mieres, town, Asturias provincia (province) and comunidad autónoma (autonomous community), northwestern Spain. Mieres lies south-southeast of Oviedo city. Until 1836 it was governed by the municipal corporation of Lena, but since that time it has been an independent administrative entity. The parish church of San Juan, originally established by a grant of King Ordoño I of Asturias in ad 857, has Romanesque columns and capitals. Cattle raising and forestry were the traditional activities of the town; modern-day Mieres is a mining and industrial centre with iron, sulfur, hard and soft coal, and mercury mines nearby. It also has blast and steel furnaces, zinc smelters, and factories specializing in the manufacture of motors and machinery for mining and for general industry. Mieres is situated on the railway lines between Madrid and Gijón. Pop. (2007 est.) mun., 44,992.