Andes The Andes are the world's longest exposed mountain range. They lie as a continuous chain of highland along the western coast of South America. The range is over long, to wide (widest between 18° to 20°S latitude), and of an average height of about .The Andean range is composed principally of two great ranges, the Cordillera Oriental and the Cordillera Occidental, often separated by a deep intermediate depression, in which arise other chains of minor importance, the chief of which is Chile's Cordillera de la Costa.