Albert Barnes Commentary Joshua 10:37

"and they took it, and smote it with the edge of the sword, and the king thereof, and all the cities thereof, and all the souls that were therein; he left none remaining, according to all that he had done to Eglon; but he utterly destroyed it, and all the souls that were therein." — Joshua 10:37 (ASV)

Its king - No doubt the successor of the king slain at Makkedah (Joshua 10:23).

All its cities - that is, the smaller towns dependent upon Hebron. The expression marks Hebron as the metropolis of other subject towns.