SARNO (anc. Sarnus), a town of Campania, Italy, in the province of Salerno, 15 m. N.E. from that city and 30 m. E. of Naples by the main railway. Pop. (1901) 15,130 (town), 19,192 (commune). It lies at the foot of the Apennines, 92 ft. above sea-level, near the sources of the Sarno (anc. Sarnus), a stream connected by canal with Pompeii and the sea. Sarno has the ruins of a medieval castle, which belonged to Count Francesco Coppola, who took an important part in the conspiracy of the barons against Ferdinand of Aragon in 1485. Walter of Brienne is buried in the ancient church of S. Maria della Foce rebuilt in 1701. Paper, cotton, silk, linen and hemp are manufactured. The travertine which forms round the springs of the Sarno was used even at Pompeii as building material. Before its incorporation with the domains of the crown of Naples Sarno gave its name to a countship held in succession by the Orsini, Cappola, Suttavilla and Colonna families.