וַיְהִ֤י לָהֶם֙ גְּב֣וּל נֶ֔גֶב מִקְצֵ֖ה יָ֣ם הַמֶּ֑לַח מִן־הַלָּשֹׁ֖ן הַפֹּנֶ֥ה נֶֽגְבָּה׃
And their south border was from the uttermost part of the Salt Sea, from the bay that looked southward.
Read midrashic interpretation of Joshua 15:2: and classical rabbinic exegesis.