Althepus was in Greek mythology a son of the Greek god Poseidon and Leïs, a daughter of Orus, king of Troezen. The territory of Troezen was called "Althepia" after him. In his reign Poseidon and Athena disputed the possession of the country with each other.
This article incorporates text from a publication now in the public domain: Smith, William, ed. (1870). "article name needed". Dictionary of Greek and Roman Biography and Mythology.