Volterra (Anc. Volaterroe), a town of Tuscany, Italy, in the province of Pisa, on an elevated plateau between the Era on the north and the Cecina on the south, 30 m. S. W. of Florence; pop. about 6,000. It retains more of its original Etruscan character than any other Italian city. It is the seat of a bishop and of a college and episcopal seminary, and has a remarkable cathedral, the sacristy of which is especially rich in relics, and many other interesting churches and palaces. In the vicinity are salt and borax springs, salines, coal mines, and quarries of marble, gypsum, and alabaster, the last being largely manufactured. The old citadel contains the dungeon, il mastio di Volterra, where the mathematician Lorenzini and others were incarcerated, and the whole building is now used as a prison. - Volaterrae was one of the oldest and most important of the Etruscan cities. It adhered to the Latins in their war with Tarquinius Priscus, resisted L. Cornelius Scipio Barbatus in the beginning of the 3d century B. C, and subsequently in the same century became a dependent ally of Rome. It was the last stronghold of Marius in Italy, and did not surrender to the troops of Sulla till after a two years' siege.
Its inhabitants received the rights of Roman citizens, and were protected by Cicero from the effort made during his consulship to dispossess them of their territory by an agrarian law. There are no allusions to it in the history of the Roman empire, but after the fall of the western empire it again came into notice as a stronghold in the wars of the Goths with Narses. Of the ruins and antiquities of the city, the most remarkable are two of the ancient gates, one, the Porta all' Arco, retaining perfect its sculptured arch.