John Gill Commentary Joshua 12:8

"in the hill-country, and in the lowland, and in the Arabah, and in the slopes, and in the wilderness, and in the South; the Hittite, the Amorite, and the Canaanite, the Perizzite, the Hivite, and the Jebusite:" — Joshua 12:8 (ASV)

In the mountains, and in the valleys, and in the plains, and
in the springs, and in the wilderness, and in the south country
Which is a description of the whole land of Canaan; some parts of which were hills and mountains, others vales and champaign fields; others were dry and barren, and others well watered; some part of it lay to the north, as towards Lebanon, and others to the south, towards Seir:

the Hittites, the Amorites, and the Canaanites, the Perizzites, the
Hivites, and the Jebusites ;
which were the nations that inhabited the land of Canaan before it was taken and possessed by the Israelites.