​NICASTRO, a town and episcopal see of Calabria, Italy, in the province of Catanzaro, 17 m. W.N.W. of Catanzaro by rail, and 5½ m. E. of S. Eufemia, a station on the line along the ​west coast from Naples to Reggio di Calabria. Pop. (1901) 13,671 (town), 18,150 (commune). It is situated on the isthmus between the gulfs of S Eufemia and of Squillace, the narrowest part of Calabria, 970 ft. above sea-level, and commands a fine view. The ruined castle served as the place of imprisonment of Frederick II.'s son Henry. The place suffered greatly from the earthquake of 1638, which also destroyed the Benedictine abbey of S Eufemia, founded by Robert Guiscard.