As he had promised, God brought Israel into the land. Joshua then focused on dividing the land among Israel's tribes.
The tribal allowances made the covenant of the Israelites with God real. It showed the fulfillment of God's promise to Abraham, Isaac, and Jacob. Since God owned the land, giving it to the tribes was a gift. God gave them the land to live in and guided its distribution.
In these lists of tribal allowances, the author describes some borders in great detail, allowing them to be mapped. With others, they are less plainly defined.