And at the stream of the brooks. Rather, "and the pouring ( וְאֶשֶׁד) of the brooks," i.e; the slope of the watershed. Ar. עָר is an archaic form of עִיר, a city. The same place is called Ar Moab in Numbers 21:28.
It was situate on the Arnon somewhat lower down than where the Israelites crossed its "brooks." The peculiarity of the site, "in the midst of the river" (Joshua 13:9, cf. Deuteronomy 2:36), and extensive ruins, have enabled travelers to identify the spot on which it stood at the junction of the Mojeb (Arnon) and Lejum (Nahaliel, Numbers 21:19).
It is uncertain whether the Greeks gave the name of Areopolis, as Jerome asserts, to Ar, but in later times it was Rabbah, a town many miles further south in the heart of Moab which bore this name. Ar was at this period the boundary town of Moab, and as such was respected by the Israelites (Deuteronomy 2:9, Deuteronomy 2:29).