Karaj is one of the metropolises of Iran and also the center of Alborz province. Karaj is one of the mountainous cities in Iran that is located in the Alborz Range and at a height of 1300 meters above sea level. According to the official statistics of 1390, the population of this city is 1,614,626, which is now considered to be the fourth most populated city of Iran after the cities of Tehran, Mashhad and Isfahan. Karaj is second largest migratory city of Iran (after Tehran), and its population is younger than other major cities in Iran. Karaj is now one of the major metropolises in Iran. The city has the highest population growth among metropolitan areas with an annual population growth of 14.3%.