‘And the border of Manasseh was from Asher to Michmethath which is before Shechem, and the border went along to the right hand, to the inhabitants of Entappuah. The land of Tappuah belonged to Manasseh, but Tappuah on the border of Manasseh belonged to the children of Ephraim. And the border descended to the river Kanah, southward of the river. These cities belonged to Ephraim among the cities of Manasseh.'
This is a very brief summary of the border relying on familiarity. ‘Asher' may have been in some way connected with the southern border of Asher later described (at the north west corner of Manasseh) or more probably relates to a town of that name, whereabouts now unknown, possibly north of Michmethath. Michmethath was east of (‘before') Shechem.
“And the border went along to the right hand, to the inhabitants of Entappuah.” This means southward, to the right hand of someone facing the Jordan. Tappuah, a border town, seemingly belonged to Ephraim (Joshua 16:8-9) but some of the peoples of the area were in Manasseh. It was possibly Sheikh Abu Zarad, about twelve kilometres south of Shechem.
To reach Tappuah the border descended to the south side of the Wadi Qana. ‘These cities' are presumably those already mentioned, the border cities Michmethath and Tappuah, and possibly Asher, which while seen as on territory belonging to Manasseh, themselves belonged to Ephraim. Joshua 17:9 a should be seen as connected with Joshua 17:8.
Joshua 17:9-10 (9b-10)
And the border of Manasseh was on the north side of the river, and its goings out were at the sea. Southwards it was Ephraim's, and northwards it was Manasseh's, and the sea his border, and they reached to Asher on the north, and to Issachar on the east.'
The Wadi Qanah ran west from the watershed at the head of the Michmethath valley, eight kilometres (five miles) south west of Shechem. Its lower course ran on to the Great Sea. The border between Ephraim and Manasseh was at first southward, as above, and then northward of the river bed until it reached the Great Sea. The Great Sea was its western border.
“And they reached to Asher on the north, and to Issachar on the east.” ‘They' means the children of Manasseh. This vague definition connecting them with Asher to the north west and Issachar to the east of Asher may have been deliberately vague because at this time the borders were not exactly fixed.