Deuteronomy 3:15-16

3:15 I gave Gilead to Machir. 3:16 To the Reubenites and Gadites I allocated the territory extending from Gilead as far as Wadi Arnon (the exact middle of the wadi was a boundary) all the way to the Wadi Jabbok, the Ammonite border.

sn Machir was the name of another descendant of Manasseh (cf. Num 32:41; 1 Chr 7:14-19). Eastern Manasseh was thus divided between the Jairites and the Machirites.