Bactria /ˈbæktriə/ (Bactrian: βαχλο, Bakhlo), or Bactriana, was an ancient region in Central Asia. Bactria proper was north of the Hindu Kush mountain range and south of the Oxus river, covering the flat region that straddles modern-day Afghanistan. More broadly Bactria was the area north of the Hindu Kush, west of the Pamirs and south of the Tian Shan, covering modern-day Tajikistan and Uzbekistan as well, with the Amu Darya flowing west through the centre. Bactrian, an Eastern Iranian language, was the common language of Bactria and surroundings areas in ancient and early medieval times.