The Yarmouk River (Arabic: نهر اليرموك, "Nahr Al-Yarmuk"; Hebrew: נהר הירמוך, "Nehar HaYarmukh"; Greek: Hieromax) is the largest tributary of the Jordan River. It drains much of the Hauran Plateau. It is one of three main Tributaries which enter the Jordan between the Sea of Galilee and the Dead Sea. To the south, are the Jabbok/Zarqa and the Arnon/Wadi Mujib) rivers. The Yarmouk forms the border between Israel and Jordan close to the Jordan Valley and between Syria and Jordan further upstream. It is the southern boundary of the Golan Heights. The important Battle of Yarmouk, where the Muslim Arabs defeated the Byzantine Empire, took place south of the river in 636.
Coordinates: 32°42′32.35″N 35°41′35.7″E / 32.7089861°N 35.69325°E