(ancient Volsinium or Vulsinium), a town of the Papal States, in the delegation of Viterbo, and ten miles S. by E. of Orvieto. It is situated on the north shore of the lake of the same name (Lago di Bolsena); but is chiefly remarkable for the remains of the ancient city in its vicinity, among which are numerous granite columns, supposed to have formed part of the temple of the Etruscan goddess Norcia. This was one of the most ancient and powerful of the Etruscan cities. After a series of struggles with the Romans, the Volsinians were finally subdued, their city razed to the ground, and themselves obliged to settle in a less defensible site in the plain. The new city was the birthplace of Sejanus, the favourite of Tiberius. It is now a miserable village of 1700 inhabitants.

The lake of Bolsena is about ten miles in length by eight in breadth, and surrounded by well-wooded hills. It contains two small islands, and discharges its waters by means of the Marta into the Mediterranean. The surrounding country is extremely unhealthy.