Hiddekel
Hiddekel is the ancient name of the river known later as the Tigris. Two passages mention it — the geographic prologue of Eden in Genesis and Daniel's riverside vision in the Persian period.
A River of Eden
In the description of the four rivers that branch from the river of Eden, Hiddekel is the third: "And the name of the third river is Hiddekel: that is it, which goes in front of Assyria. And the fourth river is the Euphrates" (Gen 2:14). The locator "in front of Assyria" matches the course of the Tigris along the eastern flank of the Assyrian heartland, with the Euphrates named alongside as the fourth.
The Place of Daniel's Vision
Daniel's final great vision opens on the bank of the same river. He notes both the date and the place: "in the four and twentieth day of the first month, as I was by the side of the great river, which is Hiddekel" (Dan 10:4). The same name that appears in the Eden geography returns here as a real-world setting in Babylon, identifying the Tigris by its older designation.