In its extreme eastern section, between the passes of Karambar and Baroghil (Barowghil; 12,480 feet), the eastern Hindu Kush region is not very high and has mountains that often take the form of rounded domes. Farther to the west the main ridge rises rapidly to Baba Tangi (21,368 feet) and becomes rugged, after which, within the space of about 100 miles, are concentrated the highest mountains of the entire region--about two dozen summits of more than 23,000 feet in elevation. A first cluster of high peaks around Urgand, Afg. (23,094 feet), is followed farther south by the massif (principal mountain mass) of Saraghrara (24,111 feet). Another line of imposing mountains, which includes Mounts Langar (23,162 feet), Shachaur (23,346 feet), Udrem Zom (23,376 feet), and Nadir Shah Zhara (23,376 feet), leads to the three giant mountains of the Hindu Kush, which are Mounts Noshaq (Nowshak; 24,557 feet), Istoro Nal (24,242 feet), and Tirich Mir. Most major glaciers of the Hindu Kush--among them Kotgaz, Niroghi, Atrak, and Tirich--are in the valleys of this section.
The central section from the Dorah Pass to the Shebar Pass separates the traditional Afghan regions of Badakhshan to the north and Nurestan and Kuhestan (Kohistan) around the upper Kabul River to the south. The concentration of high summits in this region creates from some vantage points the appearance of an unbroken horizon, a phenomenon known as Gipfelflur (German: "summit plain"). Maximum heights, which are lower than those in the eastern section, include Koh-i-Bandakor (22,451 feet), Koh-i-Mondi (20,498 feet), and Mir Samir (19,878 feet). These peaks are surrounded by a host of lesser mountains. Glaciers are poorly developed, but the mountain passes--which include Putsigram (13,450 feet), Veran (15,400 feet), Ram Gol (15,400 feet), and Anjoman (13,850 feet)--are high, thus making transmontane communications difficult.
The mountains of the western region fan out gradually toward the Afghan town of Herat, near the Iranian border, declining into hills of lesser importance. Communication is easier in this region, as the passes, such as the Shebar Pass (9,800 feet), have long since been crossed by roads.
A wider definition of the Hindu Kush would include a fourth region known as Hindu Raj in Pakistan. This is formed by a long, winding chain of mountains--with some lofty peaks, such as Mounts Darkot (22,447 feet) and Buni Zom (21,499 feet)--which strikes southward from the Lupsuk Peak (18,861 feet) in the eastern region, then continues to the Lawarai Pass (12,100 feet) and beyond to the Kabul River. If this chain were to be considered as part of the Hindu Kush, then the outlying mountains of the Swat Kohistan region of Pakistan to the south would also form part of the complex.
International boundaries running through the Hindu Kush are primarily those of Pakistan and Afghanistan. The Karambar Pass lies about 40 miles west of the Afghan-Chinese border, while to the west the Hindu Kush, strictly considered, approaches the border between Afghanistan and Iran without extending into Iranian territory. Between these extremes the Pakistan-Afghanistan border follows the main watershed of the Hindu Kush throughout its eastern region, from Lupsuk Peak just north of the Karambar Pass to the Dorah Pass just south of Mount Tirich Mir. Not far from the Dorah Pass the boundary leaves the main watershed and follows minor spurs until it crosses the Kabul River, continuing along the crest of the Spin Ghar Mountains toward the south. The Khyber Pass once constituted an important strategic gateway because it cut through the Spin Ghar instead of through the Hindu Kush, thus offering a comparatively easy route between the valley of the Kabul and the plains of Punjab; the pass lost its importance after it was superseded by a more accessible pass to the north.
The erratic boundary line is the result of a series of compromises reached at the end of the 19th century between the British and the ruler of Afghanistan; called the Durand Line for the British negotiator Sir Mortimer Durand, it has been inherited by the modern states of Pakistan and Afghanistan. Another curious configuration established about the same time and as yet unchanged is the Vakhan region (Wakhan Corridor), a panhandle of Afghan territory designed to act as a buffer between British India and tsarist Russia.
