Afghanistan, officially the Islamic Emirate of Afghanistan, is a landlocked country located at the crossroads of Central and South Asia. It is bordered by Pakistan to the east and south, Iran to the west, Turkmenistan to the northwest, Uzbekistan to the north, Tajikistan to the northeast, and China to the northeast and east. Occupying 652,864 square kilometers (252,072 sq mi) of land, the country is predominantly mountainous with plains in the north and the southwest, which are separated by the Hindu Kush mountain range. Kabul is the country's capital and largest city. Afghanistan's population is estimated to be between 35 and 50 million.