Somontano borders the comarcas of Sobrarbe and Alto Gállego to the north, Ribagorza and La Litera to the east, Cinca Medio to the southwest, the Monegros desert to the south and Hoya de Huesca to the west.

As its Latin name suggests, Somontano, meaning "beneath the mountain", lies at the foothills of the Pyrenees.

The primary economy of the area has always been agricultural and livestock farming based.

The area is also home to the Sierra de Guara, a vast Open Space preserve with canyons and gorges and over 60 limestone caves with prehistoric cave paintings, which led UNESCO to declare it as a World Heritage Site in 1998.

Abiego, Adahuesca, Alquézar, Azara, Azlor, Barbastro, Barbuñales, Berbegal, Bierge, Castejón del Puente, Castillazuelo, Colungo, Estada, Estadilla, El Grado, Hoz y Costean, Ilche, Laluenga, Laperdiguera, Lascellas-Ponzano, Naval, Olvena, Peralta de Alcofea, Peraltilla, Pozán de Vero, Salas Altas, Salas Bajas, Santa María de Dulcis and Torres de Alcanadre