Cities near the King's Highway included Edrei in the north along with Punon and Petra (Sela, see 2Kings 14:7) in the south. Petra, known as the rose-red city, was the capital of the Nabatean Arabs.
Why was it important?
This royal pathway was the most important north-south Biblical trading route that existed east of the Jordan River and the Dead Sea.
Caravans conveyed spices, perfumes, precious stones, cattle and other goods from the Arabian Peninsula along the king's route (1Kings 10:2, Ezekiel 27:21). Important minerals such as copper and iron (Deuteronomy 8:9), mined between the Dead Sea and the Gulf of Aqaba, were also transported along this ancient thoroughfare.
The route's southern terminus at the port city of Ezion-geber allowed goods to be trading throughout the region. Solomon utilized the King's route and used Ezion-geber, Israel's only access to the Red Sea, as a means to funnel tremendous wealth into his kingdom (1Kings 9:26 - 28, 10:11, 22, 2Chronicles 8:17).
War of kings
Chedorlaomer was the king of Elam. Angered that the rulers of Sodom and Gomorrah rebelled against him, he led a military coalition that plundered and subjugated several peoples along the King's Highway (Genesis 14:1 - 2, 4 - 5). His campaign, the first war in the Bible, began with overcoming the giant warriors living in Ashtaroth (Genesis 14:5). He then destroyed the Zuzims, Emims and Horites as he journeyed south to El-paran (near Ezion-geber).
The first Biblical mention of this famous route, by name, takes place toward the end of Moses' life. He requests, from Edom's King, that the migrating Israelites be allowed to follow the royal pathway through his land as they journey to claim their inheritance.
"Let us pass, I pray you, through your country. We will not pass through a field, nor through a vineyard, neither will we drink of the water of a well. We will go by the king's highway. We will not turn to the right hand nor to the left until we have passed your borders." (Numbers 20:17, HBFV).
The Edomites terse refusal of Moses' request, and threat of war, force God's people to travel a much longer distance to avoid the king's route (Numbers 20:18 - 21).
A short time later the Israelites attempt, yet again, to traverse north near the highway but this time through Amorite controlled lands (Numbers 21:21 - 22). The hostile Amorites, led by Sihon, not only refuse passage but also launch an attack against God's people! They are decimated, however, and their land seized by Israel (see Joshua 13).
The King's Highway served as a vital commercial and military route from before the time of Abraham, through the reigns of David and Solomon, and beyond.