Head town of the parish of the same name, located on the left bank of the Nalón River, at an average altitude of 150 meters. It has just under a thousand inhabitants.

Olloniego has traditionally been a strategic place, located next to a pass of the Nalón river through which the royal road that linked the Asturian center with the Plateau ran. In this passage a bridge was built and in its vicinity the defensive tower of the Muñiz, evolved in the medieval and modern centuries into a palatial structure, owned by the Bernaldo de Quirós. The bridge fell into disuse after a natural diversion of the river that occurred in 1676, which forced the construction of a large bridge in the following century, the work of Manuel Reguera.

Olloniego had a great development in the 20th century as a result of mining activity.