A charnel ground (Sanskrit: श्मशान; IAST: śmaśāna; Tibetan pronunciation: durtrö; ) is an above-ground site for the putrefaction of bodies, generally human, where formerly living tissue is left to decompose uncovered. Although it may have demarcated locations within it functionally identified as burial grounds, cemeteries and crematoria, it is distinct from these as well as from crypts or burial vaults.
In a religious sense, it is also a very important location for sadhana and ritual activity for Indo-Tibetan traditions of Dharma particularly those traditions iterated by the Tantric view such as Kashmiri Shaivism, Kaula tradition, Esoteric Buddhism, Vajrayana, Mantrayana, Dzogchen, and the sadhana of Chöd, Phowa and Zhitro, etc. The charnel ground is also an archetypal liminality that figures prominently in the literature and liturgy and as an artistic motif in Dharmic Traditions and cultures iterated by the more antinomian and esoteric aspects of traditional Indian culture.
India
Throughout Ancient India and Medieval India, charnel grounds in the form of open air crematoria were historically often located along rivers and many ancient famous charnel sites are now 'sanitized' pilgrimage sites (Sanskrit: tirtha) and areas of significant domestic income through cultural tourism. However, proper "charnel grounds" can still be found in India, especially near large rivers banks and areas where abandoned people (without family) are cremated or simply left to decompose. These areas are often frequented by Aghoris, a Kapalika sect, that follows similar meditation techniques, as those thought by the 84 Mahasiddhas. A typical Aghori sadhana (at the charnel ground) lasts for 12 years.
Himalayan 'sky burial'
In the Himalaya where tillable topsoil for burial and fuel for cremation is scarce and a valuable commodity, the location of a so-called sky burial is identified with a charnel ground.
Sutrayana and Early Buddhism
In the Pali Canon discourses, Gautama Buddha frequently instructs his disciples to seek out a secluded dwelling (in a forest, under the shade of a tree, mountain, glen, hillside cave, charnel ground, jungle grove, in the open, or on a heap of straw). The Vinaya and Sutrayana tradition of the "Nine Cemetery Contemplations" (Pali: nava sīvathikā-manasikāra) described in the Satipatthana Sutta demonstrate that charnel ground and cemetery meditations were part of the ascetic practices in Early Buddhism.
'Cemetery contemplations', as described in Mahasatipatthana Sutta (DN: 22) and the Satipaṭṭhāna Sutta (MN: 10):
Polysemy and metaphor
On the face of it or alternatively the cosmetic level, the charnel ground is simply a locality often chthonic where bodies are disposed of, either by cremation or burial. Though the charnel ground is to be understood as a polysemy and metaphor it must be emphasized that holy people as part of their sadhana and natural spiritual evolution grappling with death, impermanence and transition did historically in India, China and Tibet as well as in other localities, frequent charnel grounds, crematoriums and cemeteries and were often feared and despised by people who did not understand their 'proclivities' (Sanskrit: anusaya).
From a deeper structural significance and getting to the substantive bones of the Vajrayana spiritual point of view however, the charnel ground is full of profound transpersonal significance. It represents the 'death of ego' (Sanskrit: atmayajna), and the end of: attachment (Sanskrit: Upādāna; Tibetan: len pa) to this body and life craving (Sanskrit: ; Tibetan: sred pa) for a body and life in the future fear of death (Sanskrit: abhiniveśa) aversion (Sanskrit: dveṣa; Wylie: zhe sdang) to the decay of 'impermanence' (Sanskrit: anitya). It is worth noting that 'attachment', 'craving', 'fear' and 'aversion' above cited in bold font are somewhat standardized and hence less-rich lexical choices for the semantic field represented by the four of the 'Five Poisons' (Sanskrit: pancha klesha) they denote.
Prior to spiritual realization, charnel grounds are to be understood as terrifying places, full of 'roaming spirits' (Sanskrit: gana) and 'hungry ghosts' (Sanskrit: pretas) indeed localities that incite consuming fear. In a charnel ground there are bodies everywhere in different states of decomposition: freshly dead bodies, decaying bodies, skeletons and disembodied bones.
Simmer-Brown (2001: p. 127) conveys how the 'charnel ground' experience may present itself in the modern Western mindstream situations of emotional intensity, protracted peak performance, marginalization and extreme desperation: