(nachal ha-gadh; the King James Version River of Gad):

In 2Sa 24:5 we read that Joab and the captains of the host passed over Jordan and pitched in Aroer, on the right side of the city that is in the midst of the valley of Gad.

If we refer to Jos 13:25 f, this might seem to indicate a valley near Rabbath-ammon. According to a generally accepted emendation suggested by Wellhausen, however, we should read, "They began from Aroer, and from the city that is in the middle of the torrent valley, toward Gad."

See AR. The valley is evidently the Arnon. W. Ewing

Additional Material

GAD, VALLEY OF (TOWARD) (הַנַּ֥חַל הַגָּ֖ד). The phrase “toward Gad,” occurs in the RSV (2 Sam 24:5). The KJV has “the river of Gad,” whereas the ASV has “the Valley of Gad.” It identifies the point where David’s census began. The “Aroer” of the context is prob. the city on the N bank of the Arnon, and therefore the “river” or “valley” would be the Arnon.