35°19′19.5″N 69°1′37.0″E / 35.322083°N 69.026944°E
The Salang Tunnel (Dari: تونل سالنگ Tūnel-e Sālang, Pashto: د سالنگ تونل Da Sālang Tūnel) is a 2.67-kilometre-long (1.66 mi) tunnel located at the Salang Pass in northern Parwan Province of Afghanistan, about 90 km (56 mi) north of the nation's capital, Kabul. At nearly 3,400 m (11,200 ft) above sea level, the tunnel work was originally completed by the Soviet Union in 1964.
The Kushan Pass or Kaoshan Pass (el. about 4,370 m or 14,340 ft) is a mountain pass just west of the famous Salang Pass (3,878 m. or 12,723 ft.) in the Hindu Kush mountain range of northern Afghanistan. These two passes provided the most direct, if difficult, routes across the imposing east–west wall of the Hindu Kush mountains which divide northern Afghanistan or Tokharistan from Kabul province, which is closely connected to southern Afghanistan and Pakistan. Nowadays, the Salang tunnel constructed by the Soviets in the 1960s, and the paved road through it make it by far the easiest route through the Hindu Kush Mountains.
Vincent Smith states that Alexander the Great took his troops across both the Khawak Pass and the Kaoshān or Kushan Pass.