The Payoshṇī is a sacred river of the Deccan. It is also called Pūrṇā or Paishṭhī. The Mahābhārata names it in the Vana Parva, among the tīrthas (sacred places) visited in the tīrtha-yātrā (pilgrimage) that Lomaśa told to the Pāṇḍavas.

In the Mahābhārata

The Payoshṇī appears in the Mahābhārata’s account of the tīrtha-yātrā as an important river-tīrtha of the Deccan. The Mahābhārata describes its sacred character and the puṇya (merit) gained on its banks. It lists the river among those where rites for the ancestors bring liberation to the pitṛs. For this reason it is a favoured place for śrāddha rites. Bathing in the Payoshṇī and doing rites on its banks bring great merit, especially for the ancestors.

Which river it is

The Payoshṇī is sometimes identified with the Pūrṇā river, a branch of the Tāpī in the Vidarbha region, or with another river on the Maharashtra plateau. The tradition looks first to the river’s spiritual character, and not to its exact place on the map.

Sources

Mahābhārata, Vana Parva (the tīrtha-yātrā told by Lomaśa)