Khorasan

Province in northeast Iran, bordering on Turkmenistan and Afghanistan; area 313,500 sq km/121,042 sq mi; population (1991) 6,013,200. The capital is Mashhad. Khorasan is Iran's largest province. The chief products are grain, tobacco, cotton, fruits, and wool. There are turquoise mines at Neyshabur.

In the early Middle Ages the name Khorasan was applied to all the Muslim provinces east of the Great Persian Desert, and all of northeastern Iran, southern Turkmenistan, and northern Afghanistan. In medieval times it was divided into four quarters, the main towns of which were Neyshabur, Marv, Herat, and Balkh.