Deuteronomy 3:8

And we shall take in that time the land out of the hand of the two kings of the Amorites, which is on the other side Jordan from the torrent Arnon, even to mount Hermon.

Joshua 12:2-6

Sihon, king of the Amorites, dwelling in Heshbon, he ruled from Aroer, which is upon the lip of the torrent Arnon, and between the torrent and half Gilead, and even to the torrent Jabbok, the boundary of the sons of Ammon;

Joshua 13:9-12

From Aroer that is upon the lip of the torrent Arnon, and the city which is in the midst of the torrent, and all the plain of Medeba, even to Dibon;

Numbers 32:33-42

And Moses will give to them, to the sons of Gad and to the sons of Reuben, and to half the tribe of Manasseh, son of Joseph, the kingdom of Sihon, king of the Amorites, and the kingdom of Og, king of Bashan, the land with its cities in the bounds, the cities of the land round about

Treasury of Scripture Knowledge

Summary

And we took at that time out of the hand of the two kings of the Amorites the land that was on this side Jordan, from the river of Arnon unto mount Hermon;

Bible References

The land

Numbers 32:33
And Moses will give to them, to the sons of Gad and to the sons of Reuben, and to half the tribe of Manasseh, son of Joseph, the kingdom of Sihon, king of the Amorites, and the kingdom of Og, king of Bashan, the land with its cities in the bounds, the cities of the land round about
Joshua 12:2
Sihon, king of the Amorites, dwelling in Heshbon, he ruled from Aroer, which is upon the lip of the torrent Arnon, and between the torrent and half Gilead, and even to the torrent Jabbok, the boundary of the sons of Ammon;
Joshua 13:9
From Aroer that is upon the lip of the torrent Arnon, and the city which is in the midst of the torrent, and all the plain of Medeba, even to Dibon;