Geologically, the Indian subcontinent was first a part of so-called "Greater India", a region of Gondwana that drifted away from East Africa about 160 million years ago, around the Middle Jurasic period. The Indian subcontinent, Australia and islands of Indian Ocean rifted further, drifting northeastwards, with the Indian subcontinent colliding with the Eurasian plate nearly 55 million years ago, towards the end of Palaeocene. This collision created the Himalayas, including the Hindu Kush.
The Hindu Kush range remains geologically active and are still rising. It is prone to earthquakes.
The origins of the name Hindu Kush are uncertain, with multiple theories being propounded by different scholars and writers. The Persian-English dictionary indicates that the word 'koš' [kʰoʃ] is derived from the verb ('koštan' کشتن [kʰoʃˈt̪ʰæn]), meaning "to kill". The word and suffix "-kush" means "kill, slay, death". According to one interpretation, the name Hindu Kush means "kills the Hindu" or "Hindu killer" and is a reminder of the days when slaves from the Indian subcontinent died in the harsh weather typical of the Afghan mountains while being taken to Central Asia.
In his travel memoirs about India, the 14th century Moroccan traveller Muhammad Ibn Battuta mentioned crossing into India via the mountain passes of the Hindu Kush. In his Rihla, he mentions these mountains and the history of the range in slave trading. He wrote,
After this I proceeded to the city of Barwan, in the road to which is a high mountain, covered with snow and exceedingly cold; they call it the Hindu Kush, that is Hindu-slayer, because most of the slaves brought thither from India die on account of the intenseness of the cold.
According to Nigel Allan, the term Hindu Kush has been commonly seen to mean "Hindu killer", but two other meanings of the term include "sparkling snows of India" and "mountains of India" with "Kush" possibly a soft variant of Kuh which means "mountain". To Arab geographers, states Allan, Hindu Kush was the frontier boundary where Hindustan started.
According to McColl, yet another possibility is that the name may be from the ancient Avestan language, with the meaning "water mountain".
The mountain range was also called "Paropamisadae" by Hellenic Greeks in the late first millennium BC.
Some 19th century Encyclopedias and gazetteers state that the term Hindu Kush originally applied only to the peak in the area of the Kushan Pass, which had become a center of the Kushan Empire by the first century.
Some scholars remove the space, and refer to Hindu Kush as "Hindukush".
The mountains have historical significance in the Indian subcontinent and China. The Hindu Kush range was a major center of Buddhism with sites such as the Bamiyan Buddhas. It has also been the passageway during the invasions of the Indian subcontinent, a region where the Taliban and Al Qaeda grew, and to modern era warfare in Afghanistan.
Buddhism was widespread in the ancient Hindu Kush region. Ancient artwork of Buddhism include the giant rock carved statues called the Bamiyan Buddha, in the southern and western end of the Hindu Kush. These statues were blown up by the Taliban Islamists. The southeastern valleys of Hindu Kush connecting towards the Indus Valley region were a major center that hosted monasteries, religious scholars from distant lands, trade networks and merchants of ancient Indian subcontinent.
One of the early Buddhist schools, the Mahāsāṃghika-Lokottaravāda, was prominent in the area of Bamiyan. The Chinese Buddhist monk Xuanzang visited a Lokottaravāda monastery in the 7th century CE, at Bamiyan, Afghanistan. Birchbark and palm leaf manuscripts of texts in this monastery's collection, including Mahāyāna sūtras, have been discovered in the caves of Hindu Kush, and these are now a part of the Schøyen Collection. Some manuscripts are in the Gāndhārī language and Kharoṣṭhī script, while others are in Sanskrit and written in forms of the Gupta script.
According to Alfred Foucher, the Hindu Kush and nearby regions gradually converted to Buddhism by the 1st century CE, and this region was the base from where Buddhism crossed the Hindu Kush expanding into the Oxus valley region of Central Asia. After the Islamic conquest of the region and Islam becoming the state religion, Buddhism vanished and locals became Muslims.
The significance of the Hindu Kush mountain range has been recorded since the time of Darius I of Persia. Alexander the Great entered the Indian subcontinent through the Hindu Kush as his army moved past Bactria into the Afghan valley in the spring of 329 BCE. He moved towards the Indus valley river region in 327 BCE, his armies building several towns in this region over the intervening two years.
After Alexander the Great's death in 323 BCE, the region became part of the Seleucid Empire, according to the ancient history of Strabo written in 1st century BCE, before it became a part of the Indian Maurya Empire around 305 BCE. The region became a part of the Kushan Empire in centuries around the start of the common era.
The lands north of the Hindu Kush, in the Hephthalite dominion, Buddhism was the predominant religion by mid 1st millennium CE. These Buddhists were religiously tolerant and they co-existed with followers of Zoroastrianism, Manichaseism and Nestorian Christianity. This Central Asia region along the Hindu Kush was taken over by Western Turks and Arabs by the eighth century, facing wars with mostly Iranians. One major exception was the period in mid to late seventh century, when the Tang dynasty from China destroyed the Northern Turks and extended its rule all the way to Oxus River valley and regions of Central Asia bordering all along the Hindu Kush.
The subcontinent side and valleys of the Hindu Kush remained unconquered by the Islamic armies till the 9th century, even though they had conquered the southern regions of Indus River valley such as Sind. Kabul fell to the army of Al-Ma'mun, the seventh Abbasid caliph, in 808 and the local king agreed to accept Islam and pay annual tributes to the caliph. However, states André Wink, inscriptional evidence suggests that Kabul area near Hindu Kush had an early presence of Islam.
Mahmud of Ghazni came to power in 998 CE, in Ghazna, Afghanistan south of Kabul and Hindu Kush range. He began a military campaign that rapidly brought both sides of the Hindu Kush range under his rule. From his mountainous Afghan base, he systematically raided and plundered kingdoms in north India from east of the Indus river to west of Yamuna river seventeen times between 997 and 1030. Mahmud of Ghazni raided the treasuries of kingdoms, sacked cities and destroyed Hindu temples, with each campaign starting every spring, but he and his army returned to Ghazni and Hindu Kush base before monsoons arrived in the northwestern part of the subcontinent. He retracted each time, only extending Islamic rule into western Punjab.
In 1017, the Iranian Islamic historian Al-Biruni was deported after a war that Mahmud of Ghazni won, to northwest Indian subcontinent under Mahmud's rule. Al Biruni stayed in the region for about fifteen years, learnt Sanskrit and translated many Indian texts, and wrote about Indian society, culture, sciences and religion in Persian and Arabic. He stayed for some time in the Hindu Kush region, particularly near Kabul. In 1019, he recorded and described a solar eclipse in what is modern era Laghman Province of Afghanistan through which Hindu Kush pass. Al Biruni also wrote about early history of the Hindu Kush region and Kabul kings, who ruled the region long before he arrived, but this history is inconsistent with other records available from that era. Al Biruni was supported by Sultan Mahmud. Al Biruni found it difficult to get access to Indian literature locally in the Hindu Kush area, and to explain this he wrote, "Mahmud utterly ruined the prosperity of the country, and performed wondeful exploits by which the Hindus became the atoms scattered in all directions, and like a tale of old in the mouth of the people. (...) This is the reason, too, why Hindu sciences have retired far from those parts of the country conquered by us, and have fled to places which our hand cannot yet reach, to Kashmir, Benares and other places".
In late 12th century, the historically influential Ghurid empire led by Mu'izz al-Din ruled the Hindu Kush region. He was influential in seeding the Delhi Sultanate, shifting the base of his Sultanate from south of the Hindu Kush range and Ghazni towards the Yamuna River and Delhi. He thus helped bring the Islamic rule to the northern plains of Indian subcontinent.
The Moroccan traveller Ibn Battuta arrived in the Delhi Sultanate by passing through the Hindu Kush. The mountain passes of the Hindu Kush range were used by Timur and his army and they crossed to launch the 1398 invasion of northern Indian subcontinent. Timur, also known as Temur or Tamerlane in Western scholarly literature, marched with his army to Delhi, plundering and killing all the way. He arrived in the capital Delhi where his army looted and killed its residents. Then he carried the wealth and the captured slaves, returning to his capital through the Hindu Kush.
Babur, the founder of Mughal Empire, was a patrilineal descendant of Timur with roots in Central Asia. He first established himself and his army in Kabul and the Hindu Kush region. In 1526, he made his move into north India, won the Battle of Panipat, ending the last Delhi Sultanate dynasty, and starting the era of the Mughals.
Slavery, as with all major ancient and medieval societies, has been a part of Central Asia and South Asia history. The Hindu Kush mountain passes connected the slave markets of Central Asia with slaves seized in South Asia. The seizure and transportation of slaves from Indian subcontinent became intense in and after the 8th century CE, with evidence suggesting that the slave transport involved "hundreds of thousands" of slaves from India in different periods of Islamic rule era. According to John Coatsworth and others, the slave trading operations during the pre-Akbar Mughal and Delhi Sultanate era "sent thousands of Hindus every year north to Central Asia to pay for horses and other goods". However, the interaction between Central Asia and South Asia through the Hindu Kush was not limited to slavery, it included trading in food, goods, horses and weapons.
The practice of raiding tribes, hunting and kidnapping people for slave trading continued through the 19th century, at an extensive scale, around Hindu Kush. According to a British Anti-Slavery Society report of 1874, the Governor of Faizabad, Mir Ghulam Bey, kept 8,000 horses and cavalry men who routinely captured non-Muslim infidels (kafir) as well as Shia Muslims as slaves. Others alleged to be involved in slave trade were feudal lords such as Ameer Sheer Ali. The isolated communities in the Hindu Kush were one of the targets of these slave hunting expeditions.
In early 19th century, the Sikh Empire expanded under Ranjit Singh in the northwest till the Hindu Kush range.
The Hindu Kush served as a geographical barrier to the British empire, leading to paucity of information and scarce direct interaction between the British colonial officials and Central Asian peoples. The British had to rely on tribal chiefs, Sadozai and Barakzai noblemen for information, and they generally downplayed the reports of slavery and other violence for geo-political strategic considerations.
In the colonial era, the Hindu Kush were considered, informally, the dividing line between Russian and British areas of influence in Afghanistan. During the Cold War the Hindu Kush range became a strategic theatre, especially during the 1980s when Soviet forces and their Afghan allies fought the Mujahideen with support from the US allies channeled through Pakistan. After the Soviet withdrawal and the end of the Cold War, many Mujahideen morphed into Taliban and Al Qaeda forces imposing a strict interpretation of Islamic law (Sharia), with Kabul, these mountains and other parts of Afghanistan as their base. Other Mujahideen joined the Northern Alliance to oppose the Taliban rule.
After September 11, 2001 terror attacks in New York, the American and ISAF campaign against Al Qaeda and their Taliban allies made the Hindu Kush once again a militarized conflict zone.
The Hindu Kush are a formidable mountain range to cross with most peaks between 14,500 and 17,000 feet, with some much higher. They experience heavy snowfall and blizzards, with the lowest mountain pass through them being southern Shibar pass (9,000 feet) where the Hindu Kush range terminates. Other mountain passes being generally about 12,000 or higher. They become passable in late spring and summer.
The mountains of the Hindu Kush range diminish in height as they stretch westward. Near Kabul, they extend from 4,500 to 6,000 meters (14,800 to 19,700 ft); in the west, they attain heights of 3,500 to 4,000 meters (11,500 to 13,100 ft). The average altitude of the Hindu Kush is 4,500 meters (14,800 feet).
The Hindu Kush system stretches about 966 kilometres (600 mi) laterally, and its median north-south measurement is about 240 kilometres (150 mi). Only about 600 kilometres (370 mi) of the Hindu Kush system is called the Hindu Kush mountains. The rest of the system consists of numerous smaller mountain ranges. Rivers that flow from the mountain system include the Helmand River, the Hari River and the Kabul River, watersheds for the Sistan Basin.
Numerous high passes ("kotal") transect the mountains, forming a strategically important network for the transit of caravans. The most important mountain pass is the Salang Pass (Kotal-e Salang) (3,878 m); it links Kabul and points south of it to northern Afghanistan. The completion of a tunnel within this pass in 1964 reduced travel time between Kabul and the north to a few hours. Previously access to the north through the Kotal-e Shibar (3,260 m) took three days. The Salang tunnel at 3,363 m and the extensive network of galleries on the approach roads were constructed with Soviet financial and technological assistance and involved drilling 1.7 miles through the heart of the Hindu Kush. The Salang tunnel is on Afghan Highway 76, northwest of Golbahar town, and has been an active area of armed conflict with various parties trying to control it.
These mountainous areas are mostly barren, or at the most sparsely sprinkled with trees and stunted bushes. Very ancient mines producing lapis lazuli are found in Kowkcheh Valley, while gem-grade emeralds are found north of Kabul in the valley of the Panjsher River and some of its tributaries. The famous 'balas rubies', or spinels, were mined until the 19th century in the valley of the Ab-e Panj or Upper Amu Darya River, considered to be the meeting place between the Hindu Kush and the Pamir ranges. These mines now appear to be exhausted.
The Eastern Hindu Kush range, also known as the High Hindu Kush range, is mostly located in northern Pakistan and the Nuristan and Badakhshan provinces of Afghanistan. The Chitral District of Pakistan is home to Tirich Mir, Noshaq, and Istoro Nal, the highest peaks in the Hindu Kush. The range also extends into Ghizar, Yasin Valley, and Ishkoman in Pakistan's Northern Areas.
Chitral is considered to be the pinnacle of the Hindu Kush region. The highest peaks, as well as countless passes and massive glaciers, are located in this region. The Chiantar, Kurambar, and Terich glaciers are amongst the most extensive in the Hindu Kush and the meltwater from these glaciers form the Kunar River, which eventually flows south into Afghanistan and joins the Bashgal, Panjshir, and eventually the much smaller Kabul River.
Pre-Islamic populations of the Hindu Kush included Shins, Yeshkun, Chiliss, Neemchas Koli, Palus, Gaware, Yeshkuns, and Krammins.