Chizkuni
ויסעו מהרי העברים ויחנו בערבות מואב, “they journeyed from the mountains of Avarim and encamped in the plains of Moav. This journey had been referred to in Parshat Chukat as: “from Matanah to Nachliel.” (verse 19). Once the people had come to this location, they gradually spread out in different directions on that plain.