The Metallifere hills are the largest range in the Tuscan Appennines, located in the western portion of Tuscany.
The range runs through four provinces: the southeast part of Livorno, the southern part of Pisa, the southwestern part of Siena and the northwestern part of Grosseto. Excluding the Poggio di Montieri and Cornate di Gerfalco peaks (both over 1,000 m), the majority of the range is hilly and rich in various local minerals.
The area between Pisa and Grosseto is noted for its geothermal energy which manifests in sulfur geysers.
The area includes various cities and towns: Sassetta, Campiglia Marittima and Suvereto in the Livorno province, Monteverdi Marittimo, Pomarance and Castelnuovo di Val di Cecina in the Pisa province, Radicondoli and Chiusdino in the Siena province, Monterotondo Marittimo, Montieri, Roccastrada, Massa Marittima, Gavorrano, Scarlino and the northern part of Castiglione della Pescaia in the Grosseto province.
During Etruscan times, the Metallifere hills were known for their mineral outcrops; extraction continued for centuries and reached its peak in the second half of the 19th and first half of the 20th centuries before it began to rapidly decline. In order to service the mineral mining, a railroad route was built. It is now almost completely defunct.