Adam Clarke on Joshua 11:17

From the mount Halak - All the mountainous country that extends from the south of the land of Canaan towards Seir unto Baal-gad, which lies at the foot of Mount Libanus or Hermon, called by some the mountains of Separation, which serve as a limit between the land of Canaan and that of Seir; see Jos 12:7.

The valley of Lebanon - The whole extent of the plain which is on the south, and probably north, of Mount Libanus. Calmet conjectures that Coelesyria is here meant.