Sierro is a municipality of Almería province, in the autonomous community of Andalusia, Spain, It is located in the valley of the River Sierro in the 'Comarca del Mármol', county of the marble.

The village is now mainly populated by descendants of people from Murcia and Albacete, with a few from Castile and the rest from Andalusia.

Francisco Jimenez Ontiveros, engineer and lawyer, belonged to Sierro's most prominent family, which included his brother, Federico Jimenez Ontiveros, a medical doctor, hospital director in Seville, and General in the Spanish Air Force.

The then-family home dominates the fountain square in the village and has a plaque dedicated to Federico.

It also had a long history of municipal service with family members serving as mayors and town secretaries.