Greater Khorasan

Khorasan (Middle Persian: , Persian: خراسان‎‎  listen ) is a historical region lying in the northeast of Persia. "In pre-Islamic and early Islamic times, the term "Khurassan" frequently had a much wider denotation, covering also parts of Central Asia and Afghanistan; early Islamic usage often regarded everywhere east of western Persia, so-called Djibal or what was subsequently termed 'Irak 'Adjami, as being included in a vast and ill-defined region of Khurasan, which might even extend to the Indus Valley and Sind."

Khorasan in its proper sense comprised principally the cities of Balkh and Herat (now in Afghanistan), Mashhad and Nishapur (now in northeastern Iran), Merv and Nisa (now in southern Turkmenistan), and Bukhara and Samarkand (now in Uzbekistan). Some believe that at certain times Khorasan covered a wider area, which included parts of Transoxiana, Soghdiana, Sistan, and extended to the boundaries of the Indian subcontinent. When the Arabs first arrived to the southern Hindu Kush to defeat the Zunbils, they recognized it as al-Hind (Sind), owing to the prevalence of Buddhists and Hindus (non-Zoroastrians) due to its cultural connection with Greater India. Sources from the 14th to the 16th century report that areas in the south of the Hindu Kush mountain range (Zamindawar, Balochistan, and Kabulistan) formed a frontier between Khorasan and Hindustan.