נֶ֣גְבָּה לְאֶפְרַ֗יִם וְצָפ֙וֹנָה֙ לִמְנַשֶּׁ֔ה וַיְהִ֥י הַיָּ֖ם גְּבוּל֑וֹ וּבְאָשֵׁר֙ יִפְגְּע֣וּן מִצָּפ֔וֹן וּבְיִשָּׂשכָ֖ר מִמִּזְרָֽח׃
Rashi on Joshua
The southern side belonged to Ephraim: Ephraim took his share from the south, facing the land between the descendants of Yehudah and the rest of the tribes.
Rashi on Joshua
The northern side belonged to Menashe. Menashe took the land to the north.