Read Joshua 15:5 Using Other Translations
And the east border was the salt sea, even unto the end of Jordan. And their border in the north quarter was from the bay of the sea at the uttermost part of Jordan:
And the east boundary is the Salt Sea, to the mouth of the Jordan. And the boundary on the north side runs from the bay of the sea at the mouth of the Jordan.
The eastern boundary extended along the Dead Sea to the mouth of the Jordan River. The northern boundary began at the bay where the Jordan River empties into the Dead Sea,