And at that time came Joshua, and cut off the Anakims from the mountains, from Hebron, from Debir, from Anab, and from all the mountains of Judah, and from all the mountains of Israel: Joshua destroyed them utterly with their cities. (Joshua 11:21)
That is, at the time of the continuance of the war as described above.
This cannot be merely a recapitulation of the military operations described in ch. 10:36-41. In many cases territory once conquered was reoccupied by the original inhabitants on the withdrawal of the victorious Israelites, and had to be recovered by further conquests. This was the case with Hebron and the towns in its vicinity, Debir and Anab (see Joshua 11:21; 15:15-17; Judges 1:19, 20). The cutting off of the sons of Anak is particularly mentioned, because they had been a terror to the spies 40 years before. The spies had represented their size and strength as an insuperable barrier to the conquest of Canaan (Num. 13:28, 33).
The Anakims.
A race of gigantic stature, these may have been either aboriginals or very early immigrants from the region of the east. At first they settled on the eastern side of Jordan, but subsequently occupied the hill country of Judea and the coast cities later taken by the Philistines.