Bactria (from Βακτριανή, the Hellenized version of Bactrian; Old Persian Bāxtriš; Uzbek: Балх; Tajik: Бохтар; Vedic Sanskrit Báhlika) is the ancient name of a historical region covering the modern-day flat regions that straddle present-day Afghanistan, Pakistan, and Tajikistan. Bactria was one of the ancient civilizations of Iranian peoples. It was located south of the Pamir Mountains and the Amu Darya, surrounding the district of Gandhara (said to be its "crown jewel") to its south.
Bactria was the birthplace of Zoroastrianism, and later also hosted Buddhism before becoming Muslim after the arrival of the Rashidun and the Umayyad Caliphates in the 7th century. Bactria was also sometimes referred to by the Greeks as Bactriana.