Avestan geography in the context of "Yasht"

Bactria (/ˈbæktriə/; Bactrian: βαχλο, Bakhlo), or Bactriana, was an ancient Iranian civilization in Central Asia, located in the area south of the Oxus River (modern Amu Darya) and north of the Hindu Kush mountains, within modern-day Afghanistan, Tajikistan and Uzbekistan. Bactria was strategically located south of Sogdia and west of the Pamir Mountains. These mountain ranges acted as "walls" protecting Bactria from three sides, with the Pamir mountains to the north and the Hindu Kush to the south forming a junction, and the Karakoram range towards the east.

Called "beautiful Bactria, crowned with flags" by the Avesta, the region is considered, in the Zoroastrian faith, to be one of the "sixteen perfect Iranian lands" that the supreme deity, Ahura Mazda, had created. It was once a small and independent kingdom struggling to survive against nomadic Turanians. One of the early centres of Zoroastrianism, and capital of the legendary Kayanian dynasty, Bactria is mentioned in the Behistun Inscription of Darius the Great as one of the satrapies of the Achaemenid Empire; it was a special satrapy, ruled by a crown prince or an intended heir. Bactria was the centre of Iranian resistance against the Greek Macedonian invaders after the fall of the Achaemenid Empire in the 4th century BC, but eventually fell to Alexander the Great.

Avestan (/əˈvɛstən/ ə-VESS-tən) is the liturgical language of Zoroastrianism. It belongs to the Iranian branch of the Indo-European language family and was originally spoken during the Avestan period (c. 1500 – 400 BCE) by the Iranians living in eastern Greater Iran as evidenced from names in Avestan geography.

After Avestan became extinct, its religious texts were transmitted orally, then collected and put into writing during the Sasanian period (c. 400 – 500 CE). The extant material falls into two groups: Old Avestan (c. 1500 – 900 BCE) and Younger Avestan (c. 900 – 400 BCE). The immediate ancestor of Old Avestan was the Proto-Iranian language, a sister language to the Proto-Indo-Aryan language, with both having developed from the earlier Proto-Indo-Iranian language. As such, Old Avestan is quite close in both grammar and lexicon to Vedic Sanskrit, the oldest preserved Indo-Aryan language.

Hindus (Hindustani: [ˈɦɪndu] ; /ˈhɪnduːz/; also known as Sanātanīs) are people who religiously adhere to Hinduism, also known by its endonym Sanātana Dharma. Historically, the term has also been used as a geographical, cultural, and later religious identifier for people living in the Indian subcontinent.

It is assumed that the term "Hindu" traces back to Avestan scripture Vendidad which refers to land of seven rivers as Hapta Hendu which itself is a cognate to Sanskrit term Sapta Sindhuḥ. (The term Sapta Sindhuḥ is mentioned in Rig Veda and refers to a North western Indian region of seven rivers and to India as a whole.) The Greek cognates of the same terms are "Indus" (for the river) and "India" (for the land of the river). Likewise the Hebrew cognate hōd-dū refers to India mentioned in Hebrew Bible (Esther 1:1). The term "Hindu" also implied a geographic, ethnic or cultural identifier for people living in the Indian subcontinent around or beyond the Sindhu (Indus) River. By the 16th century CE, the term began to refer to residents of the subcontinent who were not Turkic or Muslims.

Airyanem Vaejah (Avestan: 𐬀𐬌𐬭𐬌𐬌𐬀𐬥𐬆𐬨⸱𐬬𐬀𐬉𐬘𐬀𐬵, romanized: airiianəm vaējah; Middle Persian: Ērān-wēz; Persian: Irānwēj; Parthian: Aryānwēžan, 'the Arya Expanse') is considered in Zoroastrianism to be the homeland of the early Iranians and the place where Zarathustra received the religion from Ahura Mazda. The Avesta also names it as the first of the "sixteen perfect lands" that Ahura Mazda created for the Iranians.

Based on these descriptions, modern scholarship initially focused on Airyanem Vaejah in an attempt to determine the homeland of the Iranians or Indo-Iranians in general. Among these early attempts, the region of Khwarezm emerged as a likely locale. More recent scholarship, however, no longer agrees as to where Airyanem Vaejah might have been located or to what extent it is a mythological rather than a specific historical place.

Zoroastrian or Iranian cosmology refers to the origins (cosmogony) and structure (cosmography) of the cosmos in Zoroastrianism. Zoroastrian literature describing cosmographical beliefs include the Avesta (especially in its description of Avestan geography) and, in later Middle Persian literature, texts including the Bundahishn, Denkard, and the Wizidagiha-i Zadspram.