Foroneus, in Greek mythology, was a king of Argos.
According to Pseudo-Apolodorus, he succeeded his brother Aegialeus (who died childless) and was succeeded by his son Apis.
Other ancient authors consider Foronæus as the first king of the region, or the second king of Argos, succeeding his father Inachus and being succeeded by Apis; by the calculations of Jerome of Stridus, he reigned from 1806 BCE to 1746 BCE. After his death, his brother Phegous erected a temple to him, so that he could be worshipped as a god with a sacrifice of cattle.
According to Newton, the antiquity of Foroneus was invented by Acusilau, who made Foroneus a contemporary of Ogiges and the Greek flood by bringing forward his reign by 680 years. Newton proposes a date of 1080 BCE for the founding of Phoronicum (later called Argos) by Foroneus, whose father Inacus would be an exiled shepherd king of Egypt (Hyksos).