The Yarmuk River is the largest tributary of the Jordan River. It runs in Jordan, Syria and Israel, and drains much of the Hauran plateau. Its main tributaries are the wadis of 'Allan and Ruqqad from the north, Ehreir and Zeizun from the east. Although the Yarmuk is narrow and shallow throughout its course, at its mouth it is nearly as wide as the Jordan, measuring 30 ft (9.1 m) in breadth and 5 ft (1.5 m) in depth.