Jamieson, Fausset and Brown on Numbers 13:29

29. The Amalekites dwell in the land of the south--Their territory lay between the Dead and the Red Seas, skirting the borders of Canaan.

Hittites ... dwell in the mountains--Their settlements were in the southern and mountainous part of Palestine (Ge 23:7).

the Canaanites dwell by the sea--The remnant of the original inhabitants, who had been dispossessed by the Philistines, were divided into two nomadic hordes--one settled eastward near the Jordan; the other westward, by the Mediterranean.