Cross reference
Joshua 13:10
10 and all the cities of Sihon king of the Amorite, who reigned in Heshbon, unto the border of the Bene-Ammon,
Numbers 21:24-26
24 And Israel smiteth him by the mouth of the sword, and possesseth his land from Arnon unto Jabbok -- unto the sons of Ammon; for the border of the sons of Ammon `is' strong.
25 And Israel taketh all these cities, and Israel dwelleth in all the cities of the Amorite, in Heshbon, and in all its villages;
26 for Heshbon is a city of Sihon king of the Amorite, and he hath fought against the former king of Moab, and taketh all his land out of his hand, unto Arnon;