The province is the largest in Abruzzo and occupies the western part of the region; it is the only province that has no access to the sea, and includes the highest mountains of the Apennines (Gran Sasso, Maiella and Velino-Sirente). There are many rivers, such as the Aterno-Pescara, Sangro, Liri, Salto, Turano and an abundance of springs and water coming form the abundant snowfall.
Besides the natural lakes of Scanno and Barrea, there is the large artificial lake of Campotosto. In the Gran Sasso mountain there is also the southernmost glacier in Europe, called the Calderone, which is unfortunately shrinking year after year.
All the Municipalities - I Comuni:
The province has a very low population density, and a territory full of castles and fortified medieval boroughs on top of mountains. It included once the largest lake in the Italian peninsula, Lake Fucino, where in antiquity the Romans came on holiday, which was drained with the third biggest engineering project in the late 19th century (the other 2 being the Eiffel Tower and the Suez Canal). The Fucino land is today a flourishing agricultural area, and an important technological district in the region.
The province in the past
The province included also Popoli and Bussi sul Tirino, that in 1927 were moved to the newly established province of Pescara, and other communes that were moved to the Province of Rieti: Cittaducale, Cantalice, Lugnano di Villa Troiana, Amatrice, Accumuli, Antrodoc, Borgo Velino, Castel Sant'Angelo, Micigliano, Borbona, Cittareale, Posta, Borgocollefegato, Pescorocchiano, Fiamignano, Petrella Salto, Leonessa.