Adam Clarke's Commentary on the Bible - Joshua 12:2
From Aroer - Aroer was situated on the western side of the river Arnon, in the middle of the valley through which this river takes its course. The kingdom of Sihon extended from the river Arnon and the city of Aroer on the south to the river Jabbok on the north. And from half Gilead - The mountains of Gilead extended from north to south from Mount Hermon towards the source of the river Arnon, which was about the midst of the extent of the kingdom of Sihon: thus Sihon is said to have... read more
Adam Clarke's Commentary on the Bible - Joshua 12:1
From the river Arnon unto Mount Hermon - Arnon was the boundary of all the southern coast of the land occupied by the Israelites beyond Jordan; and the mountains of Hermon were the boundaries on the north. Arnon takes its rise in the mountains of Gilead, and having run a long way from north to south falls into the Dead Sea, near the same place into which Jordan discharges itself. And all the plain on the east - All the land from the plains of Moab to Mount Hermon. read more