From the south, all the land of the Canaanites, and Mearah that is beside the Sidonians unto Aphek, to the borders of the Amorites:

Wesley's Notes

13:4 From the south - That is, from those southern parts of the sea - coast, now possessed by the Philistines, all the more northern parts of the sea - coast being yet inhibited by the Canaanites, almost as far as Sidon. The Amorites - The Amorites were a very strong and numerous people, and we find them dispersed in several parts, some within Jordan, and some without it, some in the south and others in the north, of whom he speaks here.

King James Translators' Notes

Mearah: or, the cave

Jamieson-Fausset-Brown Bible Commentary

4. all the land of the Canaanites, and Mearah-("the cave")

that is beside the Sidonians-a mountainous region of Upper Galilee, remarkable for its caves and fastnesses.

unto Aphek-now Afka; eastward, in Lebanon.

to the borders of the Amorites-a portion of the northeastern territory that had belonged to Og. The third district that remained unsubdued:

Matthew Henry's Concise Commentary

13:1-6 At this chapter begins the account of the dividing of the land of Canaan among the tribes of Israel by lot; a narrative showing the performance of the promise made to the fathers, that this land should be given to the seed of Jacob. We are not to pass over these chapters of hard names as useless. Where God has a mouth to speak, and a hand to write, we should find an ear to hear, and an eye to read; and may God give us a heart to profit! Joshua is supposed to have been about one hundred years old at this time. It is good for those who are old and stricken in years to be put in remembrance of their being so. God considers the frame of his people, and would not have them burdened with work above their strength. And all people, especially old people, should set to do that quickly which must be done before they die, lest death prevent them, Ec 9:10. God promise that he would make the Israelites masters of all the countries yet unsubdued, through Joshua was old, and not able to do it; old, and not likely to live to see it done. Whatever becomes of us, and however we may be laid aside as despised, broken vessels, God will do his own work in his own time. We must work out our salvation, then God will work in us, and work with us; we must resist our spiritual enemies, then God will tread them under our feet; we must go forth to our Christian work and warfare, then God will go forth before us.