“It went down.” This is the northern border of Ephraim going toward the east, toward the Arabah and Jordan River.
“to Ataroth.” This has to be a different Ataroth than on the south of Ephriam (Josh. 16:2, 5; 18:13), which is Ataroth-addar. The word “Ataroth” means “crown,” and there are at least three of them in the Old Testament.