Read Joshua 18:19 Using Other Translations
And the border passed along to the side of Bethhoglah northward: and the outgoings of the border were at the north bay of the salt sea at the south end of Jordan: this was the south coast.
Then the boundary passes on to the north of the shoulder of Beth-hoglah. And the boundary ends at the northern bay of the Salt Sea, at the south end of the Jordan: this is the southern border.
ran past the north slope of Beth-hoglah, and ended at the north bay of the Dead Sea, which is the southern end of the Jordan River. This was the southern boundary.