Terek Pass is an all year round pass

Mountain pass

A mountain pass is a route through a mountain range or over a ridge. If following the lowest possible route, a pass is locally the highest point on that route...

 in the Alay Mountains

Alay Mountains

The Alay or Alai Mountains is a mountain range that extends from the Tien Shan mountain range in Kyrgyzstan west into Tajikistan. It is part of the Pamir-Alay mountain system. The range runs approximately east to west. Its highest summit is Pik Tandykul , 5544 m. The southern slopes of the range...

 in the Osh

Osh

Osh is the second largest city in Kyrgyzstan, located in the Fergana Valley in the south of the country and often referred to as the "capital of the south". The city is at least 3,000 years old, and has served as the administrative center of Osh Province since 1939...

 oblast of Kyrgyzstan

Kyrgyzstan

Kyrgyzstan , officially the Kyrgyz Republic is one of the world's six independent Turkic states . Located in Central Asia, landlocked and mountainous, Kyrgyzstan is bordered by Kazakhstan to the north, Uzbekistan to the west, Tajikistan to the southwest and China to the east...

. It was historically the principal pass to enter Xinjiang

Xinjiang

Xinjiang is an autonomous region of the People's Republic of China. It is the largest Chinese administrative division and spans over 1.6 million km2...

 from the central Asia. It is also known as Terek-Davan, Terek-Dawan and Terek-Bavan pass.

Pass lies on the principal medieval trading route from Kashgar

Kashgar

Kashgar or Kashi is an oasis city with approximately 350,000 residents in the western part of the Xinjiang Uyghur Autonomous Region of the People's Republic of China. Kashgar is the administrative centre of Kashgar Prefecture which has an area of 162,000 km² and a population of approximately...

 via Irkeshtam

Irkeshtam

Irkeshtam is a village east of the Alay Valley in southern Osh Province, Kyrgyzstan. It is one of the two main border crossings between Kyrgyzstan and Xinjiang, China, the other being Torugart, some to the northeast...

 on today's Kyrgyzstan

Kyrgyzstan

Kyrgyzstan , officially the Kyrgyz Republic is one of the world's six independent Turkic states . Located in Central Asia, landlocked and mountainous, Kyrgyzstan is bordered by Kazakhstan to the north, Uzbekistan to the west, Tajikistan to the southwest and China to the east...

-China

China

Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...

 border to Osh

Osh

Osh is the second largest city in Kyrgyzstan, located in the Fergana Valley in the south of the country and often referred to as the "capital of the south". The city is at least 3,000 years old, and has served as the administrative center of Osh Province since 1939...

 and Ferghana valley.

Marko Polo crossed the pass to enter China and it was used by Genghis Khan

Genghis Khan

Genghis Khan , born Temujin and occasionally known by his temple name Taizu , was the founder and Great Khan of the Mongol Empire, which became the largest contiguous empire in history after his death....

to enter central Asia.