The land determined by lot for the clans of the Judahite tribe ran southward to the border of Edom. The Zin wasteland was the southern limit.
References for Joshua 15:1
Their south border ran from the end of the Dead Sea, from the bay that faces south.
It went south from the ascent of Akrabbim, passed on to Zin, and went up south of Kadesh-barnea. It passed on to Hezron, went up to Addar, and turned toward Karka.
It passed on to Azmon and went by the border of Egypt. The border ended at the sea. This will be their south border.
References for Joshua 15:4
The east border was the Dead Sea as far as the mouth of the Jordan. The border on the north side ran from the bay of the sea at the mouth of the Jordan.
The border went up to Beth-hoglah and passed north of Beth-arabah. The border went up to the Stone of Bohan (Reuben's son).
The border went up to Debir from the Achor Valley, turning north to Gilgal. Gilgal was opposite the ascent of Adummim, which was south of the ravine. The border passed on to the waters of En-shemesh and ended at En-rogel.
The border went up by the valley of Ben-Hinnom to the slope of the Jebusite city, Jerusalem, on the south. The border went up to the top of the mountain that is opposite the Hinnom Valley on the west, which is at the north end of the Rephaim Valley.
The border turned from the top of the mountain to the waters of Nephtoah Spring and went to the cities of Mount Ephron. The border turned toward Baalah (that is, Kiriath-jearim).
The border turned westward from Baalah to Mount Seir. It passed on to the slope of Mount Jearim on the north (that is, Chesalon), went down to Beth-shemesh, and passed by Timnah.
The border went to the slope of Ekron on the north. The border turned toward Shikkeron, passed on to Mount Baalah, and went to Jabneel. The border ended at the sea.
The west border was the Mediterranean Sea and its shoreline. This was the border surrounding the clans of the Judahites.