Abruzzo is a region of Italy, with an area of 10,763 square kms (4,156 sq mi) and a population of 1.3 million. Its western border lies east of Rome. The region is divided into the four provinces of L'Aquila, Teramo, Pescara, and Chieti. Abruzzo borders the region of Marche to the north, Lazio to the west and south-west, Molise to the south-east, and the Adriatic Sea to the east. Geographically, Abruzzo is divided into a mountainous area to the west, which includes the Gran Sasso D'italia, and a coastal area to the east with beaches on the Adriatic sea. Abruzzo is considered culturally, linguistically, and historically a region of Southern Italy, although geographically it may also be considered central. The Italian Statistical Authority (ISTAT) deems it to be part of Southern Italy, partially because of Abruzzo's historic association with the Kingdom of the Two Sicilies.