Alfeios river is the longest in Peloponnese (110km). It is flowing through the regional units of Arcadia and Elis. The Ancient highway which links Patra city and Kalamata, run along this river.
In Greek mythology, the Peneus and Alpheus were two rivers re-routed by Heracles in his fifth labour in order to clean the filth from the Augean Stables in a single day, a task which had been presumed to be impossible.