Deir ez-Zor is the seventh largest city in Syria and the largest in the eastern part of Syria. Located 450 km (280 mi) to the northeast from the capital Damascus on the shores of Euphrates River, Deir ez-Zor is the capital of the Deir ez-Zor Governorate.
The modern town was expanded by the Ottoman Empire in 1867 around the pre-existing town. In 1915, the city became a major destination point for Armenians subjected to death marches during the Armenian Genocide. A memorial commemorating the events was erected in the city in 1991. France occupied Deir ez-Zor in 1921 and made it the seat of a large garrison. Meanwhile, the region was locally ruled by Haj-Fadel Abboud, a member of an aristocratic family. In 1941 British-led forces defeated the Vichy French during the Syria-Lebanon campaign, which included a battle over Deir, and they handed administration of the region to the Free French. In 1946 it became part of the independent Republic of Syria.
Deir ez-Zor is situated 85 km (53 mi) to the northwest of the archaeological remains of Dura-Europos and 120 km (75 mi) northwest of the remains of the ancient city of Mari. During Roman times it was an important trading post between the Roman Empire and India. Conquered by Zenobia, it became part of the kingdom of Palmyra. After a successive wave of conquests, it was finally destroyed by the Mongols as they swept across the Middle East – Wikipedia