Deuteronomy 2:24
24 ‘Rise up, set out on your journey and lgo over the Valley of the Arnon. Behold, I have given into your hand Sihon the Amorite, king of mHeshbon, and his land. Begin to take possession, and ncontend with him in battle.
Deuteronomy 3:16
16 and to the Reubenites cand the Gadites I gave the territory from Gilead as far as the Valley of the Arnon, with the middle of the valley as a border, as far over as the river Jabbok, dthe border of the Ammonites;