Alfeios (112km) is the longest river in Peloponnese. It rises just outside Arcadia, which it runs across and, along its path, merges with Loussios, Elissonas and Tritonas. In Tripotama, it also merges with Erymanthos and Ladonas and widens significally. It runs across the area of Ancient Olympia and ends in the southern Ionian Sea, in the gulf of Kyparissia. Enipeas or Lestinitsa is its main affluent that rises from Foloi Range and waters a large part of the plain in the east of Pyrgos. In the antiquity, Alfeios was worshiped as a god by sacrificing bulls and building two bethels in Olympia, one of which was built by Hercules. The lying human shape of Alfeios can be seen on the eastern pediment of Zeus' temple in Olympia, in which the preparation of the chariot race between Oenomaos and Pelopas is depicted.
The most outstanding bridge on its banks is the one located in Karytena. Many rafting and canoe kayak activities are organized in Alfeios, which offer a unique way of having fun in the river.