Raqqa is a city in Syria on the northeast bank of the Euphrates River, about 160 kilometres east of Aleppo. It is located 40 kilometres east of the Tabqa Dam, Syria's largest dam. The Hellenistic, Roman, and Byzantine city and bishopric Callinicum was the capital of the Abbasid Caliphate between 796 and 809, under the reign of Harun al-Rashid. It was also the capital of the Islamic State from 2014 to 2017. With a population of 531,952 based on the 2021 official census, Raqqa is the sixth largest city in Syria.