יהושע, פרק י״ז, פסוק ח׳

Allocating the land between the tribes of Manasseh and Ephraim resulted in a complex and unique border. Because both of these tribes descended from Joseph, their territories were somewhat mixed together [ביאור שטיינזלץ]. In a broad geographical sense, the northern section of the area belonged entirely to Manasseh, while the southern section was split between Manasseh in the north and Ephraim in the south [מלבי״ם].

The primary approach among commentators highlights a clear distinction between the wider region and the local city. The geographical space surrounding the city of Tappuah, which encompassed the fields, villages, nearby courtyards, and the northern district, fell entirely within the inheritance of Manasseh. However, the actual city of Tappuah was positioned on the southern side, resting right on the very edge of Manasseh's border [רש״י, מלבי״ם]. Even though the city stood directly on this boundary line, it was ultimately given to the tribe of Ephraim.