Numbers 34:3

your southern region shall be from the Wilderness of Zin along the side of Edom, and your southern boundary from the end of the Salt (Dead) Sea eastward.

Genesis 14:3

All of these [kings] joined together [as allies] in the Valley of Siddim (that is, the Sea of Salt).

Ezekiel 47:13

Thus says the Lord God, “This shall be the boundary by which you shall divide the land as an inheritance among the twelve tribes of Israel; Joseph shall have two portions.

Exodus 23:31

I will establish your borders from the Red Sea to the Sea of the Philistines (the Mediterranean), and from the wilderness to the River Euphrates; for I will hand over the residents of the land to you, and you shall drive them out before you.

Joshua 3:16

the waters which were flowing down from above stopped and rose up in one mass a great distance away at Adam, the city that is beside Zarethan. Those [waters] flowing downward toward the sea of the Arabah, the Salt Sea, were completely cut off. So the people crossed [the river] opposite Jericho.

Joshua 15:1-12

Now the lot (allotment) for the tribe of the sons of Judah according to their families reached [southward to] the border of Edom, southward to the wilderness of Zin at its most southern part.

Ezekiel 47:8

Then he said to me, “These waters go out toward the eastern region and go down into the Arabah (the Jordan Valley); then they go toward the sea, being made to flow into the sea, and the waters of the Dead Sea shall be healed and become fresh.

Ezekiel 47:18-23

“The east side, from between Hauran, Damascus, Gilead, and the land of Israel, shall be the Jordan; from the north border to the eastern sea you shall measure. This is the east side.

Treasury of Scripture Knowledge

Summary

Then your south quarter shall be from the wilderness of Zin along by the coast of Edom, and your south border shall be the outmost coast of the salt sea eastward:

Bible References

South quarter

Exodus 23:31
I will establish your borders from the Red Sea to the Sea of the Philistines (the Mediterranean), and from the wilderness to the River Euphrates; for I will hand over the residents of the land to you, and you shall drive them out before you.
Joshua 15:1
Now the lot (allotment) for the tribe of the sons of Judah according to their families reached [southward to] the border of Edom, southward to the wilderness of Zin at its most southern part.
Ezekiel 47:13
Thus says the Lord God, “This shall be the boundary by which you shall divide the land as an inheritance among the twelve tribes of Israel; Joseph shall have two portions.

Salt sea eastward

Joshua 3:16
the waters which were flowing down from above stopped and rose up in one mass a great distance away at Adam, the city that is beside Zarethan. Those [waters] flowing downward toward the sea of the Arabah, the Salt Sea, were completely cut off. So the people crossed [the river] opposite Jericho.
Joshua 15:2
Their southern border was from the lower end of the Salt (Dead) Sea, from the bay that turns southward.
Ezekiel 47:8
Then he said to me, “These waters go out toward the eastern region and go down into the Arabah (the Jordan Valley); then they go toward the sea, being made to flow into the sea, and the waters of the Dead Sea shall be healed and become fresh.