Cerro de los Almadenes, Archaeological site in Otero de Herreros, Spain

Cerro de los Almadenes is a Roman-era mining and metallurgical site on a granite hill in Otero de Herreros, Segovia. The hill lies between the Arroyo de la Escoria to the north and the Arroyo del Quejigal to the south, where mine entrances, spoil heaps and water channels are found. A skarn in the granite holds copper veins that were worked.

Claude Domergue first mapped Cerro de los Almadenes as the only copper-production site in the northern Meseta during the Early Imperial period. On the western slope he found artificial terraces with Italic terra sigillata fragments, suggesting a habitation area. The hill was declared a Bien de Interés Cultural by the Junta de Castilla y León on 9 June 2022.

The hilltop was a metalworking center for generations, and local people knew it as a place where miners extracted copper ore and workers processed metal. The traces of this labor remain visible in the landscape today, reflecting the skills of those who worked there long ago.

The site lies between two streams: the Arroyo de la Escoria to the north, now dry, and the Arroyo del Quejigal to the south, whose steeper slope keeps a little water after winter. The hill is open dehesa grazed by livestock, with small holm oaks and quejigos along the streams. Ground is uneven around the mine entrances, spoil heaps and water channels, so wear sturdy footwear and watch your footing.

Claude Domergue was the first archaeologist to place the Cerro de los Almadenes on a map of the Iberian Peninsula, listing it in his work on Roman-era mines as the only copper production site in the northern Meseta during the Early Imperial period. On the hill's western slope he recorded artificial terraces with Italic terra sigillata fragments, which he linked to a possible habitation area. Otero de Herreros honoured him on 26 June 2016.