Zanskar is a subdistrict or tehsil of the Kargil district, which lies in the eastern half of the Indian state of Jammu and Kashmir. The administrative centre is Padum. Zanskar, together with the neighbouring region of Ladakh, was briefly a part of the kingdom of Guge in Western Tibet.

The Zanskar Range is a mountain range in the Indian state of Jammu and Kashmir that separates Zanskar from Ladakh. Geologically, the Zanskar Range is part of the Tethys Himalaya, an approximately 100-km-wide synclinorium formed by strongly folded and imbricated, weakly metamorphosed sedimentary series. The average height of the Zanskar Range is about 6,000 m (19,700 ft). Its eastern part is known as Rupshu.

Zanskar appears as “Zangskar” mostly in academic studies in social sciences (anthropology, gender studies). Older geographical accounts and maps may use the alternate spelling "Zaskar". An etymological study (Snellgrove and Skorupsky, 1980) of the name reveals that its origin might refer to the natural occurrence of copper in this region, the Tibetan word for which is “Zangs”. The second syllable however seems to be more challenging as it has various meanings: “Zangs-dkar” (white copper), “Zangs-mkhar” (copper palace), or “Zangs-sKar” (copper star). Others claim it derives from zan = copper + skar = valley.[1] Crook (1994) partly shares this interpretation but suggests that the origin of this name might also be “Zan-mKhar” (food palace), because the staple food crops are so abundant in an otherwise rather arid region.

Some of the religious scholars of the district, also cited by Snellgrove and Skorupsky (1980) and Crook (1994), hold that it was originally “bZang-dKar”, meaning good (or beautiful) and white. “Good” would refer to the triangular shape of the Padum plain, the triangle being the symbol of Dharma and religion; “white” would refer to the simplicity, goodness, and religious inclinations of the Zanskaris. Thus, even if etymologically it would be more correct to use “Zangskar”, the most frequently found spelling for this region is undoubtedly “Zanskar”.

Zanskar covers an area of some 7,000 square kilometres (2,700 square miles), at a height of between 3,500 and 7,000 metres (11,500–23,000 feet). It consists of the country lying along the two main branches of the Zanskar river. The first, the Doda, has its source near the Pensi-la (4,400 m) (14,450 ft) mountain-pass, and then flows south-eastwards along the main valley leading towards Padum, the capital of Zanskar.

The second branch is formed by two main tributaries known as Kargyag river, with its source near the Shingo La (5,091 m) (16,703 ft), and Tsarap river, with its source near the Baralacha-La. These two rivers unite below the village of Purne to form the Lungnak river (also known as the Lingti or Tsarap). The Lungnak river then flows north-westwards along a narrow gorge towards Zanskar's central valley (known locally as gzhung khor), where it unites with the Doda river to form the Zanskar river.

"The Shingo La, the main route into Zanskar from Lahaul, is an unpleasant pass. It isn't particularly high, at just 17,000 feet, but it is squalid and sordid and lacks grandeur."

The Zanskar river then takes a north-eastern course until it joins the Indus in Ladakh. High mountain ridges lie on both sides of the Doda and Lingti–kargyag valleys, which run north-west to south-east. To the south-west is the Great Himalayan Range which separates Zanskar from the Kisthwar and Chamba basins. To the north-east lies the Zanskar Range, which separates Zanskar from Ladakh. The only outlet for the whole Zanskar hydrographic system is thus the Zanskar river, which cuts a deep and narrow gorge through the Zanskar range.