Numbers 21:31
So Israel lived in Amorite territory.
Numbers 32:33-42
So Moses gave to the descendants of Gad, to the descendants of Reuben, and to the half-tribe of Joseph's son Manasseh the kingdom of Sihon, the king of the Amorites, and the kingdom of Og, the king of Bashan, the whole land with its cities, and even the territories surrounding it.
Deuteronomy 3:16-17
And I've given Gilead to the descendants of Reuben and the descendants of Gad as far as the Arnon Valley, designating the middle of the valley as its boundary, including up to the Jabbok River as a boundary with the Ammonites.
Joshua 12:1-6
This is a list of the kings who ruled the land that the Israelis conquered, and whose territories they took on the other side of the Jordan River toward the east, from the Arnon River to Mount Hermon, along with the entire eastern Jordan plain.
Joshua 13:8-12
The descendants of Reuben and descendants of Gad, along with the other half-tribe of Manasseh, received their inherited portion that Moses the servant of the LORD had given them to the east beyond the Jordan River.