The earliest inhabitants of the Tarim Basin may be the Tocharians whose languages are the easternmost group of Indo-European languages.
Caucasoid mummies have been found in various locations in the Tarim Basin such as Loulan, the Xiaohe Tomb complex, and Qäwrighul.
These mummies have been suggested to be of Tocharian origin, and these people may have inhabited the region since at least 1800 BCE.
 They may be related to the "Yuezhi" (Chinese 月氏; Wade–Giles: Yüeh-Chih) mentioned in Chinese texts.
Protected by the Taklamakan Desert from steppe nomads, elements of Tocharian culture survived until the 7th century, at the dawning of the 800s with the arriving Turkic immigrants from the collapsing Uyghur Khaganate of modern-day Mongolia began to absorb the Tocharians to form the modern-day Uyghur ethnic group.

Another people in the region besides Tocharian are the Indo-Iranian Saka people who spoke various Eastern Iranian Khotanese Scythian or Saka dialects.
 In the Achaemenid-era Old Persian inscriptions found at Persepolis, dated to the reign of Darius I (r. 522-486 BC), the Saka are said to have lived just beyond the borders of Sogdiana.
Likewise an inscription dated to the reign of Xerxes I (r. 486-465 BC) has them coupled with the Dahae people of Central Asia.
The contemporary Greek historian Herodotus noted that the Achaemenid Persians called all of the Indo-Iranian Scythian peoples as the Saka.
 They were known as the Sai (塞, sāi, sək in archaic Chinese) in ancient Chinese records.
These records indicate that they originally inhabited Ili and Chu River valleys of modern Kazakhstan.
 In the Chinese Book of Han, the area was called the "land of the Sai", i.e. the Saka.
 Presence of a people believed to be Saka has also been found in various location in the Tarim Basin, for example in the Keriya region at Yumulak Kum (Djoumboulak Koum, Yuansha) around 200 km east of Khotan, with a tomb dated to as early as the 7th century BC.

According to the Sima Qian's Shiji, the nomadic Indo-European Yuezhi originally lived between Tengri Tagh (Tian Shan) and Dunhuang of Gansu, China.
However, the Yuezhi were assaulted and forced to flee from the Hexi Corridor of Gansu by the  forces of the Xiongnu ruler Modu Chanyu, who conquered the area in 177-176 BC (decades before the Han Chinese conquest and colonization of Gansu or the establishment of the Protectorate of the Western Regions).
In turn the Yuezhi were responsible for attacking and pushing the Sai (i.e. Saka) west into Sogdiana, where in the mid 2nd century BC the latter crossed the Syr Darya into Bactria, but also into the Fergana Valley where they settled in Dayuan, southwards towards northern India, and eastward as well where they settled in some of the oasis city-states of the Tarim Basin.
 Whereas the Yuezhi continued westward and conquered Daxia around 177-176 BC, the Sai (i.e. Saka), including some allied Tocharian peoples, fled south to the Pamirs before heading back east to settle in Tarim Basin sites like Yanqi (焉耆, Karasahr) and Qiuci (龜茲, Kucha).
 The Saka are recorded as inhabiting Khotan by at least the 3rd century and also settled in nearby Shache (莎車), a town named after the Saka inhabitants (i.e. saγlâ).
Although the ancient Chinese had called Khotan Yutian (于闐), it's more native Iranian names during the Han period were Jusadanna (瞿薩旦那), derived from Indo-Iranian Gostan and Gostana, the names of the town and region around it, respectively.
The earliest inhabitants of the Tarim Basin may be the Tocharians whose languages are the easternmost group of Indo-European languages. Caucasoid mummies have been found in various locations in the Tarim Basin such as Loulan, the Xiaohe Tomb complex, and Qäwrighul. These mummies have been suggested to be of Tocharian origin, and these people may have inhabited the region since at least 1800 BCE.  They may be related to the "Yuezhi" (Chinese 月氏; Wade–Giles: Yüeh-Chih) mentioned in Chinese texts. Protected by the Taklamakan Desert from steppe nomads, elements of Tocharian culture survived until the 7th century, at the dawning of the 800s with the arriving Turkic immigrants from the collapsing Uyghur Khaganate of modern-day Mongolia began to absorb the Tocharians to form the modern-day Uyghur ethnic group.
Another people in the region besides Tocharian are the Indo-Iranian Saka people who spoke various Eastern Iranian Khotanese Scythian or Saka dialects.  In the Achaemenid-era Old Persian inscriptions found at Persepolis, dated to the reign of Darius I (r. 522-486 BC), the Saka are said to have lived just beyond the borders of Sogdiana. Likewise an inscription dated to the reign of Xerxes I (r. 486-465 BC) has them coupled with the Dahae people of Central Asia. The contemporary Greek historian Herodotus noted that the Achaemenid Persians called all of the Indo-Iranian Scythian peoples as the Saka.  They were known as the Sai (塞, sāi, sək in archaic Chinese) in ancient Chinese records. These records indicate that they originally inhabited Ili and Chu River valleys of modern Kazakhstan.  In the Chinese Book of Han, the area was called the "land of the Sai", i.e. the Saka.  Presence of a people believed to be Saka has also been found in various location in the Tarim Basin, for example in the Keriya region at Yumulak Kum (Djoumboulak Koum, Yuansha) around 200 km east of Khotan, with a tomb dated to as early as the 7th century BC.
According to the Sima Qian's Shiji, the nomadic Indo-European Yuezhi originally lived between Tengri Tagh (Tian Shan) and Dunhuang of Gansu, China. However, the Yuezhi were assaulted and forced to flee from the Hexi Corridor of Gansu by the  forces of the Xiongnu ruler Modu Chanyu, who conquered the area in 177-176 BC (decades before the Han Chinese conquest and colonization of Gansu or the establishment of the Protectorate of the Western Regions). In turn the Yuezhi were responsible for attacking and pushing the Sai (i.e. Saka) west into Sogdiana, where in the mid 2nd century BC the latter crossed the Syr Darya into Bactria, but also into the Fergana Valley where they settled in Dayuan, southwards towards northern India, and eastward as well where they settled in some of the oasis city-states of the Tarim Basin.  Whereas the Yuezhi continued westward and conquered Daxia around 177-176 BC, the Sai (i.e. Saka), including some allied Tocharian peoples, fled south to the Pamirs before heading back east to settle in Tarim Basin sites like Yanqi (焉耆, Karasahr) and Qiuci (龜茲, Kucha).  The Saka are recorded as inhabiting Khotan by at least the 3rd century and also settled in nearby Shache (莎車), a town named after the Saka inhabitants (i.e. saγlâ). Although the ancient Chinese had called Khotan Yutian (于闐), it's more native Iranian names during the Han period were Jusadanna (瞿薩旦那), derived from Indo-Iranian Gostan and Gostana, the names of the town and region around it, respectively.
Tarim Basin