Albert Barnes Commentary 2 Kings 10:33

"from the Jordan eastward, all the land of Gilead, the Gadites, and the Reubenites, and the Manassites, from Aroer, which is by the valley of the Arnon, even Gilead and Bashan." — 2 Kings 10:33 (ASV)

The loss of the entire trans-Jordanic territory seems to be intended, or at any rate, its complete ruin and devastation. This was the home of the tribes of Reuben, Gad, and the half-tribe of Manasseh (Joshua 22:1–9). It was more accessible from Damascus than the region west of the river.

Aroer. There were several places with this name. The one mentioned here is the most famous (compare the note on Deuteronomy 2:36).

Gilead and Bashan. The writer had previously called the whole territory "Gilead"; now he distinguishes it more accurately into Gilead, the southern region, and Bashan, the northern region (1 Kings 4:13; 1 Kings 4:19).