Joshua and Israel did not take every single city in the region. From Joshua 13:1–6 and Judges 1:19–36 we know that there were some cities that remained in Canaanite control. The last of the Canaanite cities were only subjugated during the reign of David.1 However, to the extent that they have taken the most important cities in each of the regions (northern, middle, and southern), the entire land is as good as in their hands.2 Taking the entire land thus means that Joshua has gained control of the whole region. The power of the Canaanites has been broken, and each individual tribe has the resources and men to defeat the rest of the cities in the areas of their inheritance by themselves (Joshua 13:6).
16 So Joshua took all that land, the hill country and all the Negeb and all the land of Goshen and the lowland and the Arabah and the hill country of Israel and its lowland