Irḫan was a Mesopotamian god who personified the western branch of the Euphrates, which in the first millennium BCE became its main course.
Two topics which continue to be a subject of debate among experts are his association or confusion with the snake god Nirah, and his proposed cosmogonic role.
"[1] Araḫtu grew in importance in the first millennium BCE, because the eastern branch flowing through cities such as Kish and Nippur, which was formerly the main course, became difficult to navigate.
Frans Wiggermann argues that the available evidence does not support this theory, with a possible exception being the pairing of Irḫan with Dur, a deity analogous to the cosmogonic mound, Duku, in an offering list from Ur.
[3] He points out that the god list An = Anum makes Irḫan a son of Lisin, which would not be a suitable ancestry for a cosmogonic deity.
[10] He interpreted the Kassite period personal name MUŠ-šar-ilāni, "MUŠ is the king of the gods," as referring to Irḫan as a theogonic figure.
[2] Wilfred G. Lambert assumed that Irḫan and Nirah were fully interchangeable, and related not only theophoric names with the element dMUŠ, but also the snakes depicted on kudurru (boundary stones) to him.
[18] One of the Early Dynastic Zame Hymns compares the incantation goddess Ningirima to Irḫan, presumably based on their shared connection with snakes and water.
[3] A temple dedicated to him is not directly attested, but based on the reference to a priest calling himself "the doorman of Irḫan" its existence is considered to be a possibility.