NICASTRO, a town of Naples, province of Calabria Ultra II., on a slope of the Apennines, 19 miles S. by E. of Cosenza. It is meanly built, but walled, and defended by a castle, in which Henry, eldest son of the Emperor Frederick II., was confined for having embraced the Guelph party against his father. The town is the see of a bishop, contains several churches and convents, and has some trade in oil. Pop. 6600.