Albert Barnes Commentary Joshua 18:2

"And there remained among the children of Israel seven tribes, which had not yet divided their inheritance." — Joshua 18:2 (ASV)

Two tribes and a half had already received their portions on the east of Jordan; Judah, Ephraim, and the remaining half of Manasseh had also been provided for (Joshua 15-17). Thus, there remained still seven tribes out of the twelve to be settled in their homes.