The eastern border is the Dead Sea as far north as the mouth of the Jordan River. The northern border starts from the north end of the Dead Sea at the mouth of the Jordan
From the top of that mountain the border goes around to the spring of Nephtoah. From there it goes to the cities of Mount Ephron and around to Baalah (now called Kiriath Jearim).
The border turns and goes around on the west side, south of the mountain that faces Beth Horon, and ends at Kiriath Baal (now called Kiriath Jearim), a city of Judah.