In Greek mythology, Corinthus was the eponymous founder of the city of Corinth and the adjacent land. According to the local Corinthian tradition, he was a son of Zeus, but this tradition was not followed elsewhere.
He may or may not be the same figure as:
Corinthus, son of Marathon and ruler over Corinth. When he died without issue, the Corinthians bestowed the kingdom upon Medea, because her father Aeetes had once ruled over the land before his departure to Colchis.