Bolsena, (anc. Volsinii), a town of Italy, on a lake of the same name, in the province and 56 m. N. N. W. of Rome; pop. about 2,100. Volsinii, originally built on a height in the neighborhood, was one of the most powerful Etruscan cities. It was frequently at war with the Romans, who finally took it in 280 B. C, razed it, and built a new town on the present site of Bolsena, retaining the name. Of the Etruscan town there is no vestige, and even its site is uncertain; but the remains of the Roman one are numerous, including portions of temples and of an amphitheatre, and numerous sepulchres and tumuli, in which many Etruscan vases, statues, etc, have been found. The lake of Bolsena, which is supposed to fill an ancient crater, exhales a deadly malaria during the summer season. It is about 9 m. long, 7 m. broad, and 285 ft. deep, and is famous for its eels. The shores are formed by finely wooded hills, presenting much beautiful scenery; it has two small islands, called Martana and Bisentina, and it discharges by the Marta river, flowing into the Mediterranean.