Castel di Sangro is a city and comune of 6,461 people in the Province of L'Aquila, in Abruzzo, central Italy. It is the main city of the Alto Sangr…Castel di Sangro is a city and comune of 6,461 people in the Province of L'Aquila, in Abruzzo, central Italy. It is the main city of the Alto Sangro e Altopiano delle Cinque Miglia area. Castel di Sangro is located near the Sangro River, in a valley in the Apennine Mountains.