Erymanthos  or Ollos is a great mountain and  an attraction for mountaineering and climbing with many peaks, extending as a mountain range in the northern Peloponnese, in the prefectures of Achaia and Ilia.
Its highest point is Mount Olenos or Ollos with an altitude of 2,224 meters. It is the fourth tallest mountain in the Peloponnese and is included in the so-called alpine mountains of Greece.