Adummim

Adummim names a steep ascent on the road that climbs from the Jordan fords toward Jerusalem. Both of its scriptural appearances are boundary markers — the same point read from opposite directions, marking off Judah on the south and Benjamin on the north.

On the Border of Judah

Judah's northern boundary runs through the ascent: "the border went up to Debir from the valley of Achor, and so northward, looking toward Gilgal, that is across from the ascent of Adummim, which is on the south side of the river; and the border passed along to the waters of En-shemesh, and the goings out of it were at En-rogel" (Jos 15:7). Adummim is set as a fixed landmark between the valley of Achor and En-shemesh.

On the Border of Benjamin

Benjamin's southern boundary tracks the same line from the opposite tribe: "and it extended northward, and went out at En-shemesh, and went out to Geliloth, which is across from the ascent of Adummim; and it went down to the stone of Bohan the son of Reuben" (Jos 18:17). The two notices together place Adummim at the joint frontier of Judah and Benjamin along the road from the Jordan.