Civiti Vecchia, a seaport town of Italy, on the Mediterranean, in the province and 37 m. N. W. of Rome, with which it is connected by railway; pop. about 10,000. The harbor consists of two marble piers fronted by a breakwater. The water is from 14 to 18 ft. in depth. Upon the breakwater are a lighthouse, a quarantine, docks, and a prison capable of containing 1,200 persons. The town is well built, and contains several fine churches, some monuments, and a small gallery of Etruscan antiquities. It is supplied with water by a remarkable aqueduct, constructed upon the foundations of one built by Trajan. It is the best port of central Italy on the Mediterranean, and is a stopping place for lines of steamers between Marseilles, Naples, Malta, and the Levant. Travellers going to Rome generally land here. It was founded by Trajan, who constructed its port, which was called Portus Trajani, and was one of his most remarkable works. It was destroyed by the Saracens early in the 9th century, but was rebuilt by Pope Leo IV. The fortress was commenced under Julius II., after designs by Michel Angelo, and completed under Paul III. The moles, quays, and fortifications were built upon the ancient foundations. Clement XII. made it a free port.
Its privileges were taken away in 1850, but restored in 1855.