It is part of the Antiappennini, a group running from the Apennines chain to the Tyrrhenian Sea.

Altitudes vary from hills to the 1,152 m of Cima del Nibbio and the 1,141 m of Monte Calvo.

Part of the mountains is protected by a wilderness area, which was established in 1999.

There are also species of Quercus virginiana, carpinella, aspen and laurel.

Beneath the trees are numerous rare and endemic flora, such as Crocus imperati subsp.