Siero is a municipality in Spain, in the province of Asturias, in Asturias. On 1 January 2025 it had 53,049 inhabitants according to the INE municipal register (padrón), over an area of about 212.2 km².
With about 250 inhabitants per km², it combines a medium-sized town with residential districts, farmland and business areas. Of the 29 municipalities in the province of Asturias with at least 5,000 inhabitants, it is number 4 by population.
As the crow flies it lies about 16 km east of Oviedo, the provincial capital. The nearest major city is A Coruña, about 220 km away.
Nearby, within a few dozen kilometres, are other destinations featured in our guides: Oviedo (14 km), Gijón (17 km).
Below you will find a map of neighbouring municipalities, the weather, places to stay in the area and a link to all the municipalities in the province of Asturias.