Gorgan formerly Astrabad or Astarabad is the capital city of Golestan Province, Iran. It lies approximately 400 km (250 mi) to the north east of Tehran, some 30 km (19 mi) away from the Caspian Sea. There are several archaeological sites near Gorgan, including Tureng Tepe and Shah Tepe, in which there are remains dating to the Neolithic and Chalcolithic eras. Some other important Neolithic sites in the area are Yarim Tepe, Iran, and Sange Chaxmaq. Also, the nearby Shahroud Plain has many such sites.