Illampu, mountain in western Bolivia, north of La Paz, in the Cordillera Oriental range of the Andes Mountains. Illampu overlooks Lake Titicaca, and the mountain as seen from the lake is one of the grandest scenic features in the Americas. Three principal peaks rise above the main mountain mass; the northernmost, often called Nevada Illampu to distinguish it from the other two, is 6485 m (21,276 ft) above sea level.