Castelvetrano is a town and comune in the province of Trapani, Sicily, southern Italy. The archeological site of Selinunte is located within th…Castelvetrano is a town and comune in the province of Trapani, Sicily, southern Italy. The archeological site of Selinunte is located within the municipal territory. The municipality borders with Campobello di Mazara, Mazara del Vallo, Menfi, Montevago, Partanna, Salemi and Santa Ninfa.