In Greek mythology, Inachus, Inachos or Inakhos (Ancient Greek: Ἴναχος) was the first king of Argos[1][2] after whom a river was called Inachus River,[3] that drains the western margin of the Argive plain.[4]
The kingdom of Argos, in which Inachus reigned first, arose in the time of Abraham's grandchildren...In the reign of Armamitres in Assyria and Leucippus in Sicyon as the eighth kings, and of Inachus as the first in Argos, God spoke to Isaac, and promised the same two things to him as to his father,—namely, the land of Canaan to his seed, and the blessing of all nations in his seed. These same things were promised to his son, Abraham's grandson, who was at first called Jacob, afterwards Israel, when Belocus was the ninth king of Assyria, and Phoroneus, the son of Inachus, reigned as the second king of Argos, Leucippus still continuing king of Sicyon. In those times, under the Argive king Phoroneus, Greece was made more famous by the institution of certain laws and judges. On the death of Phoroneus, his younger brother Phegous built a temple at his tomb, in which he was worshipped as God, and oxen were sacrificed to him. I believe they thought him worthy of so great honor, because in his part of the kingdom (for their father had divided his territories between them, in which they reigned during his life) he had founded chapels for the worship of the gods, and had taught them to measure time, by months and years, and to that extent to keep count and reckoning of events. Men still uncultivated, admiring him for these novelties, either fancied he was, or resolved that he should be made, a god after his death. Io also is said to have been the daughter of Inachus, who was afterwards called Isis, when she was worshipped in Egypt as a great goddess; although others write that she came as a queen out of Ethiopia, and because she ruled extensively and justly, and instituted for her subjects letters and many useful things, such divine honor was given her there after she died, that if any one said she had been human, he was charged with a capital crime.