The historical record of the Edomite kings documents a steady transfer of power from one ruler to the next. Throughout this royal lineage, the origin city of each new ruler is typically noted. However, in the case of the new king, Baal-hanan, this geographical detail is notably missing.
One way to understand this omission is that the new ruler emerged from the exact same location as his predecessor, King Shaul. Since the previous king's origin was already established in the record, there was simply no need to repeat the name of the city.
A different perspective suggests that the king's origin is actually hidden within his very title. Rather than being a traditional personal name, the title indicates his status as the master or lord of a specific region called Hanan. According to this approach, he first established his power and rose to prominence as a local ruler in that territory, before eventually being crowned over the entire nation of Edom [הטור הארוך, ביאור יש״ר].