Nahr as-Sinn (Arabic: نهر السن) is a river in Syria which marks the borders between Tartus Governorate and Latakia Governorate.
In ancient times, the river was called "Siyannu" which marked the southern borders of Ugarit.[1]
Nahr as-Sinn rises in a plain area in Tartus Governorate and runs to the west to finally flow into the Mediterranean Sea south of Arab al-Mulk. Despite its length which is only 6 kilometres (3.7 mi), it is considered the richest river in Syria.[2]
35°15′50.54″N 35°55′33.13″E / 35.2640389°N 35.9258694°E / 35.2640389; 35.9258694