Ahar (Persian: اهر‎‎, Azerbaijani: 'Əhər - اهر') is a city in and the capital of Ahar County, East Azerbaijan Province, Iran. According to the 2006 census, Ahar was the fifth most populated city of the province with a population of 85,782 in 20,844 families. Ahar was the capital of Karadag Khanate in 18th and 19th centuries.