Volsinii or Vulsinii (Etruscan: Velzna or Velusna; Greek: Ouolsinii, Ὀυολσίνιοι;Ὀυολσίνιον), is the name of two ancient cities of Etruria, one situated on the shore of Lacus Volsiniensis (modern Lago di Bolsena), and the other on the Via Clodia, between Clusium (Chiusi) and Forum Cassii (Vetralla). The latter was Etruscan and was destroyed by the Romans in 264 BC following an attempted revolt by its slaves, while the former was founded by the Romans using the remainder of the Etruscan population rescued from the razed city.
Modern Bolsena, Italy, in the region of Lazio, descends from the Roman city. The location of the Etruscan city is debated. Umbrian Orvieto, about 14 km (8.7 mi) from Bolena, is a strong candidate.
The Byzantine historian Joannes Zonaras states that the Etruscan Volsinii (Velzna or Velusna) lay on a steep height; while Bolsena, the representative of the Roman Volsinii, is situated in the plain. Scholars of the 19th century debated the location of this elevated site. Wilhelm Ludwig Abeken looks for it at Montefiascone, at the southern extremity of the lake; while Karl Otfried Müller seeks it at Orvieto, and adduces the name of that place in Latin, Urbs Vetus, the old city, as an argument in favor of his view; but British explorer and writer George Dennis is of the opinion that there is no reason to believe that it was so far from the Roman city, and that it lay on the summit of the hill, above the amphitheater at Bolsena, at a spot called Il Piazzano. He adduces in support of this hypothesis the existence of a good deal of broken pottery there, and of a few caves in the cliffs below. Bolsena is 6 km (3.7 mi) from Montefiascone, and 14 km (8.7 mi) from Orvieto.