Some believe that the name of Khorassan, attributed to a vast part of the eastern areas of Iran since the 5th century, is a combination of "Khor" (sun) and "assan" (rose). Owing to the invasion of neighbors and domestic political crises, the boundaries of Khorassan have changed in the course of history. Nevertheless, it has always comprised a vast area. The last changes in Khorassan's boundaries date back to the Qajar era, during which, in accordance with the treaty of Paris, Herat and other areas of Afghanistan were separated from Iran in 1273 A.H.

Covering an area of over 313,355 sq.km, present-day Khorassan in limited northward by Turkmenistan, westward by Yazd, Esfahan, Semnan and Mazandaran provinces and southward by Sistan, Baluchestan and Kerman provinces. Consisting of mountains, valleys, plains and deserts, Khorassan enjoys diverse climates and varying annual rainfall in its different areas.

The geographic features of Khorassan include the northern mountains of Kopedagh, middle ranges including Aladagh and Binalood, and mountains scattered in central and southern parts. Its most important rivers are Atrak, Harirood and Kashafrood. Others are often dry or have a small current. It has a variable climate, with the temperature increasing and the annual rainfall decreasing from north to south. On the basis of the latest divisions in the country (1993), Khorassan consists of 22 cities, 51 towns, 69 districts, 213 villages and 20,501 hamlets. The census of 1991 showed that its present populations exceeds 6,013,000 inhabitants. More...