The Nahr al-Kabir, also known in Syria as al-Nahr al-Kabir al-Janoubi ( Arabic: النهر الكبير الجنوبي, lit. 'the southern great river', by contrast with the Nahr al-Kabir al-Shamali) or in Lebanon simply as the Kebir, is a river in Syria and Lebanon flowing into the Mediterranean Sea at Arida. The river is 77.8 km (48.3 mi) long, and drains a watershed of 954 km2 (368 sq mi).  Its headwaters are at the Ain as-Safa spring in Lebanon and it flows through the Homs Gap.
The river forms the northern part of the Lebanon–Syria border. In antiquity, the river was known as Eleutherus ( Greek Ελεύθερος Eleutheros, Ελευθερίς Eleuteris lit. 'free'). It defined the border between the Seleucid and Ptolemaic empires during much of the 3rd century BCE. 
- United Nations Economic and Social Commission for Western Asia et al., "Nahr el Kabir Basin", Inventory of Shared Water Resources in Western Asia 8 PDF
- Dov Gera, Judaea and Mediterranean Politics: 219 to 161 B.C.E., p. 9
- Josephus, The Jewish War 1:363 pg 75 Translated by G.A.Williamson 1959, printed 1981