Heraea or Heraia () was the most important town of ancient Arcadia on the Lower Alpheius. It was situated near the frontiers of Elis, and on the high road from Arcadia to Olympia. Its territory was called the Heraeatis or Heraiatis (Ἡραιᾶτις). According to Greek mythology it was said to have been founded by Heraeus, a son of Lycaon, and to have been called originally Sologorgus. At an early period the Heraeans concluded a treaty with the Eleians for mutual protection and support for one hundred years; the original of which treaty, engraved on a bronze tablet in the old Peloponnesian dialect, was brought from Olympia, and is now in the British Museum. This treaty is placed about the 50th Olympiad, or 580 BCE, since it belongs to a time when the Eleians exercised an undisputed supremacy over the dependent districts of Pisatis and Triphylia; and the Heraeans consequently were anxious to avail themselves of their support.