[2] Although separated from the main part of the Sierra Madre del Sur by the deep canyon of the lower Río Balsas, the mountains of southern Michoacán around Coalcomán are usually considered part of the Sierra Madre del Sur.

It extends east–west for about 180 km parallel to the Pacific coast, with broad areas over 1,500 metres elevation, including Cerro Nube.

The Sierra Madre del Sur pine-oak forests ecoregion occupies the higher reaches of the range.

The Jalisco dry forests ecoregion occupies the western end of the range's Pacific slope.

Protected areas in the Sierra include the Sierra de Manantlán, Zicuirán-Infiernillo, and Tehuacán-Cuicatlán biosphere reserves, General Juan Álvarez National Park, Boquerón de Tonalá Flora and Fauna Protection Area, Omiltemi Ecological State Park, Los Olivos and El Nanchal state reserves, and the Campo Verde, Iliatenco, Cafetal San Juanito (Pluma Hidalgo), Cafetal Soconusco, Cerro Azul, Concepción Vista Hermosa, El Corozal, and El Borbollón, La Pandura y La Yerbabuena voluntary conservation areas.