'Frontier' in the Bible

From there they journeyed on and camped on the other side of [the river] Arnon, which is in the wilderness that extends from the boundary of the Amorites; for [the river] Arnon is the boundary of Moab, between Moab and the Amorites.

It continued along to Azmon and proceeded to the Brook of Egypt (Wadi el-Arish), and the border ended at the [Mediterranean] sea. This was their southern border.

Then the Israelites heard it said, “Look, the Reubenites, Gadites, and half the tribe of Manasseh have built an altar on the frontier of the land of Canaan at the region of the Jordan, on the Israelite side.”

He ruled over all the kings from the Euphrates River to the land of the Philistines, and as far as the border of Egypt.

You gave them kingdoms and nations, apportioning them as frontier boundaries. They took possession of the land of Sihon, the land of the king of Heshbon, and the land of Og, king of Bashan.

therefore I am about to expose Moab’s flank beginning with its frontier cities, the pride of the land: Beth-jeshimoth, Baal-meon, and Kiriathaim.

When they reached the frontier of Mysia, they were about to enter Bithynia, but the Spirit of Jesus would not permit this.