רַ֛ק אֶל־אֶ֥רֶץ בְּנֵי־עַמּ֖וֹן לֹ֣א קָרָ֑בְתָּ כָּל־יַ֞ד נַ֤חַל יַבֹּק֙ וְעָרֵ֣י הָהָ֔ר וְכֹ֥ל אֲשֶׁר־צִוָּ֖ה יְהוָ֥ה אֱלֹהֵֽינוּ׃
Only to the land of the children of Ammon thou camest not near; all the side of the river Jabbok, and the cities of the hill-country, and wheresoever the LORD our God forbade us.
Rashi on Deuteronomy
כל יד נחל יבק means, ALL THE DISTRICT BESIDE THE BROOK OF JABBOK.
Siftei Chakhamim
All along Wadi Yabok. (Literally, “The hand of Wadi Yabok”). Since a person’s hand is always at his side, any edge can be referred to as “hand.” See Parshas Shemos regarding the verse (2:5), “Walking on the edge (יד) of the river.”