Deuteronomy 4:46-48

46and as they camped in the valley near Beth-peor east of the Jordan River. (This land was formerly occupied by the Amorites under King Sihon, who ruled from Heshbon. But Moses and the Israelites destroyed him and his people when they came up from Egypt.

47Israel took possession of his land and that of King Og of Bashan—the two Amorite kings east of the Jordan.

48So Israel conquered the entire area from Aroer at the edge of the Arnon Gorge all the way to Mount Sirion, also called Mount Hermon.