Arnon

swift, the southern boundary of the territory of Israel beyond
Jordan, separating it from the land of Moab (Deut. 3:8, 16).
This river (referred to twenty-four times in the Bible) rises in
the mountains of Gilead, and after a circuitous course of about
80 miles through a deep ravine it falls into the Dead Sea nearly
opposite Engedi. The stream is almost dry in summer. It is now
called el-Mujeb. The territory of the Amorites extended from the
Arnon to the Jabbok.