Castello di Sassoforte, Medieval castle ruins in Sassofortino, Italy

Castello di Sassoforte is a medieval castle ruin located on a rocky crag at 780 meters elevation with commanding views of the surrounding territory. The structure features a double-walled defensive system and sits atop steep drops on all sides.

The fortification arose in the medieval period as a possession of the Aldobrandeschi family, who held it until the first half of the 14th century, when it passed under the control of Siena. The Sienese then transformed the pre-existing castle into a village. By the 15th century the site was already in ruins.

The name Sassoforte refers to the massif itself, a "strong rock" overlooking Sassofortino and Roccatederighi. The Aldobrandeschi held the fortification until the first half of the 14th century, when it passed to Siena; the Sienese then turned the castle into a village. By the 15th century the site was already in ruins, and the surviving traces recall its medieval role.

The site is best reached by taking the Florence-Siena motorway to Siena, then continuing on the Siena-Grosseto route to the Civitella Marittima exit. From there, the village of Sassofortino serves as the starting point, with walking paths leading up to the ruins.

Archaeological excavations by the University of Siena uncovered Bronze Age settlements dating from the 12th to 10th century BCE beneath the medieval ruins. These early layers reveal that the site was inhabited centuries before the castle was built.