Gihon is the title of a river first mentioned in the second chapter of the Biblical book of Genesis. The Gihon is mentioned as one of four rivers issuing out of the Garden of Eden that branched from a single river within the garden. The name (Hebrew, Gichôn) may be interpreted as "bursting forth" or "gushing".

The Gihon is described as "encircling the entire land of Cush", a name associated with Ethiopia elsewhere in the Bible. However, from a geographic standpoint, this would seem impossible, since two of the other rivers said to issue out of Eden, the Tigris and the Euphrates, are in Mesopotamia.

Fundamentalists have sought other identifications of both the "land of Cush" and the river Gihon; by some it has been associated with the Araxes (Araks) river of Turkey. Another proposed idea is that the Gihon river no longer exists, since the topography of the area has been altered by the Noachian Flood.

Secular scholars note that the Gihon river remains unidentified, since the geographical ideas of the author of Genesis cannot be reconstructed and need not conform with actual geography as known today: In Genesis 2, the Euphrates, Tigris, Gihon and Pishon rivers are all said to issue out of Eden, but the Euphrates and the Tigris do not take their rise in the same place, and the Pishon river remains as unidentified as the Gihon.

First-century Jewish historian Josephus associated the Gihon river with the Nile (Jewish Antiquities, I 39). However, a quite different Hebrew word is used to designate the Nile elsewhere in the Bible, and even in ancient times it must have been obvious that the Nile could not have a common source with the Tigris and the Euphrates.