The Fanum Voltumnae, the federal sanctuary where the twelve Etruscan cities once gathered under Voltumna's patronage, was for centuries known only from ancient literary references and had no confirmed physical location, a genuine gap in the archaeology of Etruscan political and religious life given the site's evident historical importance. That gap has narrowed substantially since excavations began in the early 2000s at Campo della Fiera, a site just outside Orvieto, under the direction of the archaeologist Simonetta Stopponi, which have uncovered a large sanctuary complex with multiple temples, altars and a paved sacred road in continuous use from the Etruscan period through the Roman era, along with inscriptions and votive material that many specialists in Etruscan archaeology now consider strong, though not universally accepted, evidence identifying the site with the long sought Fanum Voltumnae.
If the identification holds, it would place the physical center of pan-Etruscan political and religious unity at a location close to ancient Volsinii, matching the general area near Orvieto that ancient sources and modern scholars alike had long suspected, while finally supplying an excavated sanctuary complex to stand behind Varro's brief description of Voltumna as Etruria's chief god and his shrine as the league's common meeting ground. Excavation and publication of the Campo della Fiera finds continue, and the identification remains actively discussed among Etruscologists rather than fully settled, but it represents the closest modern archaeology has come to recovering physical, excavated evidence for a sanctuary that ancient political history treats as central to how the Etruscan cities understood themselves as a single people.