From thence they removed, and pitched in the valley of Zared. They - pitched in the valley of Zared - נחל זרד nachal zared. This should be translated the brook Zared, as it is in Deuteronomy 2:13, Deuteronomy 2:14. This stream has its origin in the mountains eastward of Moab, and runs from east to west, and discharges itself into the Dead Sea.
Related Commentaries of Numbers 21:12
Numbers 21:12
12 From thence they removed, and pitched in the valley of Zared.