Karaj is the capital of Alborz Province, Iran, and effectively a suburb of Tehran. Although the county hosts a population around 1.97 million, as recorded in the 2016 census, most of the 1,419 km2 (548 sq mi) county is rugged mountain, the urban area is the fourth-largest in Iran, after Tehran, Mashhad, and Isfahan. Eshtehard County and Fardis County were split off from Karaj county since the previous census.
