CASTELLAMMARE DI STABIA (anc. Stabiae), a seaport and episcopal see of Campania, Italy, in the province of Naples, 17 m. S.E. by rail from the town of Naples. Pop. (1901) town, 26,378; commune, 32,589. It lies in the south-east angle of the Bay of Naples, at the beginning of the peninsula of Sorrento, and owing to the sea and mineral water baths (12 different springs) and its attractive situation, with a splendid view of Vesuvius and fine woods on the hills behind, it is a favourite resort of foreigners in spring and autumn and of Neapolitans in summer. The castle from which it takes its name, on the hill to the south of the town, was built by the emperor Frederick II. There are three large churches of the late 18th century. There are a large royal dockyard and a small-arms factory; there are also iron works, cotton, flour and macaroni mills. The value of imports (chiefly coal, wheat, scrap-iron and cheese) for 1904 was £1,239,048, and the value of exports (chiefly macaroni and green fruit) £769,100. There is also a sponge trade, but the former coral trade is depressed. The port was cleared by 420 vessels of 477,713 tonnage in 1905. An electric tramway along the coast road to Sorrento was opened in 1905.