Within the system of cordilleras, there are three mountain masses: the Cordillera Central (Central Range), Cordillera Septentrional (Northern Range) and the Cordillera Oriental (Eastern Range).

Cordillera Central

The Cordillera Central is the largest and most important mountain group in the Dominican Republic and covers a large part of its territory. As its name indicates, it is located in the center of the country with a length of 200 km and a width of 100 km. It is the continuation of the "Northern Mass" (Massif Du Nord) found in Haitian territory; its origin dates back to the Cretaceous period. The northern slope, which is a plateau, emerged in the Oligocene period. Igneous and volcanic rocks abound in this mass, in addition to sedimentary and metamorphic rocks. The major peaks of the Antilles are found in this Cordillera: Pico Duarte; 3,175 m, La Pelona, 3,087 m; La Rusilla, 3,038 m and Pico del Yaque, 2,761 m.

The main rivers of the country also originate in this system, such as the Yaque del Norte, the Yaque del Sur, the Artibonito, the Yuna, the Nizao, the Ocoa and the Haina.

Cordillera Septentrional

The Cordillera Septentrional, second in importance to the Cordillera Central, is located in the northern section of the country, in the northwest-southeast direction and extends from Montecristi to the Gran Estero, close to Nagua. It originated in the Miocene-Oligocene periods of the Cenozoic Era, and is mostly composed of sedimentary rock. Among its most important summits is the Diego de Ocampo peak, with an elevation of 1,229 m.

Cordillera Oriental

The third mountain chain is the Cordillera Oriental, located in the eastern part of the country in a west to east direction. It originated in the Cretaceous period of the Mesozoic Era. Its elevations do not rise above 800 m.