Deuteronomy 3:16

16 But to the Reubenites and the Gadites I gave the territory extending from Gilead down to the Arnon Gorge (the middle of the gorge being the border) and out to the Jabbok River, which is the border of the Ammonites.

Read Deuteronomy 3:16 Using Other Translations

And unto the Reubenites and unto the Gadites I gave from Gilead even unto the river Arnon half the valley, and the border even unto the river Jabbok, which is the border of the children of Ammon;
and to the Reubenites and the Gadites I gave the territory from Gilead as far as the Valley of the Arnon, with the middle of the valley as a border, as far over as the river Jabbok, the border of the Ammonites;
But I also gave part of Gilead to the tribes of Reuben and Gad. The area I gave them extended from the middle of the Arnon Gorge in the south to the Jabbok River on the Ammonite frontier.