Alborz Province (Persian: استان البرز, Ostan-e Alborz) is one of the 31 provinces of Iran. It was formed by the division of Tehran Province into two provinces on June 23, 2010. Situated 35 km northwest of Tehran in the foothills of the Alborz mountains, the Province of Alborz is divided into four counties: Karaj, Savojbolagh, Taleghan and Nazarabad. Karaj is the seat of the province. Its Iran's smallest province by area. According to the National Census, in 2011 population of Alborz was 2,412,513, out of which 90.5% lived in urban areas.