Castello di Las Plassas, Medieval castle in Las Plassas, Italy.

Castello di Las Plassas is a ruined medieval castle set on top of a cone-shaped hill in the Marmilla region of central Sardinia. What remains today includes sections of stone walls and the bases of defensive towers that once enclosed the hilltop.

The castle was already standing before 1172 and served as a stronghold of the Giudicato of Arborea, one of Sardinia's medieval kingdoms. After Arborea fell to the Aragonese in 1409, the fortress lost its strategic role and was gradually abandoned.

The name Marmilla comes from the conical, breast-shaped hill beneath the castle: it first named the Arborean administrative district, then the surrounding territory, and finally the geographical sub-region. The same name is still used for the area today.

A marked path from the village leads up to the ruins on foot, and the climb is steep with little shade along the way. Sturdy shoes and water are worth bringing, especially if you visit during warmer months.

The finds from the castle excavations are kept in the MudA, the village's multimedia museum, and the ruins can be visited on their own or with a guided tour arranged there. A footpath up to the ruins was built by Alessandro Melis, a former mayor of Las Plassas who taught art history at the Marconi-Lussu lyceum in San Gavino Monreale.