Joshua 17:1, 5-6

Now this was the lot (allotment) for the tribe of Manasseh, for he was the firstborn of Joseph. To Machir the firstborn of Manasseh, the father of Gilead, were allotted Gilead and Bashan, because he was a man of war.

So ten portions fell to Manasseh, besides the land of Gilead and Bashan, which is beyond the Jordan [on the east side of the river], because the daughters of [Zelophehad, a descendant of] Manasseh had received an inheritance among his [other] sons [whose inheritance went to their male descendants]. The land of Gilead belonged to the rest of the sons of Manasseh. [Num 36:5-12]