Hazor was on the international trade route and was the largest and most important non-coastal city of Canaan (see 11:10).
Almost all of northern Canaan joined King Jabin's coalition against Israel. This region stretched from the Mediterranean Sea in the west to the desert in the east. This went from the borders of Phoenicia in the north to the hill country and the Jordan Valley in the south.
The term Jebusites usually refers to the people of Jerusalem and nearby towns under its control. Men from Jebus might have been soldiers that King Jabin hired.
Mizpah means “watchtower” or “lookout.” Several places had this name. This particular one was the large region on the lower slopes of Mount Hermon. This was the highest peak in the land that God promised Israel.