Deuteronomy 3:12-17 -

Distribution of the conquered land . The countries thus conquered by the Israelites were assigned by Moses to the tribes of Reuben and Gad and the half tribe of Manasseh. The southern portion, from Aroer, in the valley of the Amen, to the Jabbok, with its towns (see Joshua 12:15-20 , Joshua 12:24 -28), was assigned to the Reubenites and the Gadites; and the northern portion, from the Jabbok, comprehending, with Gilead, the whole of Bashan, or Argob, to the half tribe of Manasseh.