Wikipedia
Arpachshad, alternatively spelled Arphaxad or Arphacsad ( ISO 259-3 ʔarpakšad; ), was one of the five sons of Shem, the eldest son of Noah ( Genesis 10:22, 24; 11:10-13; 1 Chron. 1:17-18). Arpachshad's brothers were Elam, Asshur, Lud and Aram; he is an ancestor of Abraham. He is said by Gen. 11:10 to have been born two years after the Flood, when Shem was 100.
Arpachshad's son is called Shelah, except in the Septuagint, where his son is Cainan (קינן), Shelah being Arpachshad's grandson. Cainan is also identified as Arpachshad's son in Luke 3:36 and Jubilees 8:1. The Book of Jubilees additionally identifies Arpachshad's wife as Rasu'aya, the daughter of Susan, who was the son (or daughter in some versions) of Shem's older son Elam. (Arpachshad's mother is named in this source as Sedeqetelebab; for competing traditions on the name of Shem's wife see wives aboard the Ark.)
Some ancient Jewish sources, particularly Jubilees, point to Arpachshad as the immediate progenitor of Ura and Kesed, who allegedly founded the city of Ur Kesdim (Ur of the Chaldees) on the west bank of the Euphrates (Jub. 9:4; 11:1-7) — the same bank where Ur, identified by Leonard Woolley in 1927 as Ur of the Chaldees, is located.
Until Woolley's identification of Ur, Arpachshad was understood by many Jewish and Muslim scholars to be an area in northern Mesopotamia, Urfa of the Yazidis. This led to the identification of Arpachshad with Urfa-Kasid (due to similarities in the names ארפ־כשד and כשדים) - a land associated with the Khaldis, whom Josephus confused with the Chaldean. Donald B. Redford asserted that Arpachshad is to be identified with Babylon.
Another Arpaxad is referenced in the deuterocanonical Book of Judith as a king of the Medes, and if this supposed Median king is contemporary with the conquest of the Assyrians, he could be identified with Phraortes (c. 665 - 633 BC). If he is contemporary with Nebuchadnezzar II (named as king of the Assyrians in Judith), he might be identified with Cyaxares (r. 625–585 BC).