Herāt, velāyat (province) in western Afghanistan, 23,668 sq mi (61,301 sq km) in area, with its capital at Herāt city. It is bounded by Iran (west), by Turkmenistan and the Afghan province of Bādghīsāt (north), by Ghowr province (east), and by Farāh province (south). Herāt is relatively flat except in the east, where the western outliers of the Hindu Kush range penetrate; the largest of these is the Selseleh-ye Safīd Kūh (Paropamisus Range). The province is traversed from east to west by the Harīrūd River, along which most of the people live in agricultural oases. The capital, located in the largest oasis, is a centre of Afghan trade with Iran and Turkmenistan and is connected by roads with the neighbouring provinces.
The region corresponding to modern Herāt province has been fought over by many foreign conquerors throughout history. The Macedonian Alexander the Great took it; later it was held by Parthians, Kushans, Persians, and Hephthalites. In the 7th century Herāt fell to the Arabs, and it was conquered by the Mongols in the 13th century. Various other peoples contested its possession until its annexation by a unified Afghanistan in 1747. In 1980 a Soviet mechanized army division crossed the border from Turkmenistan (then the Turkmen Soviet Socialist Republic) and passed through Herāt city en route to Kandahār city. Intermittent heavy fighting continued in Herāt province in the early 1980s.
The Harīrūd valley is one of the nation’s richest agricultural areas, producing grain, cotton, fruit, and other crops. The province is not entirely agricultural, however: petroleum is produced at Tīr Pol, in the west, and there is some light industry at Herāt city. The people of Herāt are predominantly Tajik and Durrānī Pashtun in the oases, with seminomadic Dari-speaking peoples in the deserts and mountains. Pop. (2006 est.) 1,578,200; (2020 est.) 2,140,700.