Albert Barnes Commentary Numbers 32:37-38

"And the children of Reuben built Heshbon, and Elealeh, and Kiriathaim, and Nebo, and Baal-meon, (their names being changed,) and Sibmah: and they gave other names unto the cities which they builded." — Numbers 32:37-38 (ASV)

The Reubenites established themselves more compactly than the Gadites. Elcalch (el-’Al) a mile to the northeast; Nebo (Nebbeh) probably three miles to the southwest; Baal-meon (Main) nearly two miles to the south; Kirjathaim (Kureiyat?); and Shibmah, more properly Sibmah, famous at a later period for its vines , four miles east of Heshbon; all clustered around the old Amorite capital. The Reubenites probably retained at the partition all these cities except for Heshbon, which, passing to the Levites, was from then on counted as part of the tribe of Gad.

Neither the Reubenites nor the Gadites were “builders” in the sense of founders of the cities of which they thus took possession. They probably fortified them, whether for the first time or anew, to make them places of safety for their families during the campaigns on the other side of the Jordan, and provided them with all conveniences for their flocks and herds.