Balkan Province is one of the Welayat (provinces) of Turkmenistan. It is in the far west of the country, bordering Uzbekistan, Kazakhstan, the Caspian Sea, and Iran. Its capital is Balkanabat, formerly known as Nebit Dag. It has an area of 139,270 square kilometers and a population of approximately 553,500 people (2005 est.). Its population density of 3.3 persons per square kilometer is the lowest in Turkmenistan.