In the area of the Podere Ortaglia, locality Le Serre, where finds of material attest continuous occupation from the Iron Age onwards, a monumental and richly decorated building was erected at the end of the 6th century B.C. A landslide in a sector of the hill obliterated this building. However, the excavation of an artificial well in 2005, originally relating to the life and cult practices of the sanctuary, and which was filled in the mid 4th century B.C. with materials and rubble from the building destroyed by a violent fire, provided information regarding the characteristics of this building and some aspects of the cult. There is no documentation attesting it was a sacred area or the name of the divinity to which the sanctuary was dedicated (in fact no inscription with a divinity’s name has been found). However, the typology of the materials, including several ex-voto, some of which bear inscriptions, together with the remains of animal bones relating to sacrificial practices found inside the well, confirm the religious nature of the complex and offer clues which suggest a cult linked to a female divinity. The extension of the excavation to the base of the northern slope brought to light, below the landslide, a series of occupation levels dating to between the end of the 4th and the 2nd century B.C., documenting the reorganization of this area following the fire. If the absence of a new monumental structure, no traces of which have been found to date, is perhaps related to the changes in the Volterran context during the Hellenistic period and with the imposing restructuring, also on a monumental level, of city cult areas, the sanctuary of Ortaglia shows signs of great vitality even in this period. In this zone the excavation uncovered levels of collapse from a large late archaic/classical building, in phase with the monumental temple.