Qamishli is a city in northeastern Syria on the Syria–Turkey border, adjoining the city of Nusaybin in Turkey. The Jaghjagh River flows through the city. With a 2004 census population of 184,231, it is the ninth most-populous city in Syria and the second-largest in Al-Hasakah Governorate after Al-Hasakah. Qamishli has traditionally been a Christian Assyrian majority city, but is now predominantly populated by Kurds with large numbers of Arabs and Assyrians and a smaller number of Armenians. It is 680 kilometres (420 mi) northeast of Damascus.

The border between the Syrian Arab Republic and the Republic of Turkey is about 909 kilometres (565 mi) long, and runs from the Mediterranean Sea in the west to the tripoint with Iraq in the east. It runs across Upper Mesopotamia for some 400 kilometres (250 mi), crossing the Euphrates and reaching as far as the Tigris. Much of the border follows the Southern Turkish stretch of the Baghdad Railway, roughly along the 37th parallel between the 37th and 42nd eastern meridians. In the west, it almost surrounds the Turkish Hatay Province, partly eating the course of the Orontes River and reaching the Mediterranean coast at the foot of Jebel Aqra.