Sierra de las Minas is a mountain range in eastern Guatemala, extending 130 km west of the Lake Izabal. It is 15-30 km wide and bordered by the valleys of the rivers Polochic in the north and the Motagua in the south. Its western border is marked by the Salamá River valley which separates it from the Sierra de Chuacús range. The highest peak is Cerro Raxón at 3,015 m.
The range has several different habitats, including Mesoamerica's largest cloud forests, and is home to a great variety of wildlife. A large part of the Sierra de las Minas was declared a biosphere reserve in 1990.