Deuteronomy 3:12
"And this land, which we possessed at that time, from Aroer, which is by the river Arnon, and half mount Gilead, and the cities thereof, gave I unto the Reubenites and to the Gadites."
Cross References (ranked by relevance)
Deuteronomy 2:36
From Aroer, which is by the brink of the river of Arnon, and from the city that is by the river, even unto Gilead, there was not one city too strong for us: the LORD our God delivered all unto us:
2 Kings 10:33
From Jordan eastward, all the land of Gilead, the Gadites, and the Reubenites, and the Manassites, from Aroer, which is by the river Arnon, even Gilead and Bashan.
Deuteronomy 4:48
From Aroer, which is by the bank of the river Arnon, even unto mount Sion, which is Hermon,