From Joshua 12:13–15 we know that there were other cities that were also captured by Joshua (Geder, Hormah, Arad, and Adullam). The fact that they are not mentioned by name suggests that these seven cities are a summary account showing the destruction of representative cities. It is not meant to give a comprehensive list of all the cities captured.1
28 As for Makkedah, Joshua captured it on that day and struck it, and its king, with the edge of the sword. He devoted to destruction every person in it; he left none remaining. And he did to the king of Makkedah just as he had done to the king of Jericho.