John Gill Commentary Joshua 12:1

"Now these are the kings of the land, whom the children of Israel smote, and possessed their land beyond the Jordan toward the sunrising, from the valley of the Arnon unto mount Hermon, and all the Arabah eastward:" — Joshua 12:1 (ASV)

Now these [are] the kings of the land which the children of Israel smote In the days of Moses, as Jarchi remarks, and as it clearly appears from what follows.

and possessed, their land on the other side Jordan toward the rising of the sun on the east of the land of Canaan.

from the river Arnon unto the mount Hermon, and all the plain on the east Arnon was the border of Moab between them and the Amorites, (Numbers 21:13); and from hence to Hermon, a mountain adjoining to Lebanon, lay the country of the two kings of the Amorites after mentioned, (Deuteronomy 3:8Deuteronomy 3:9); and the plain on the east were the plains of Moab, which lay to the east of Jordan.