Uṣṇīgaṁga (Ushniganga) was a pious river created from the Bhṛgutuṁga (Bhrigutunga) parvata. In the text of Haridāsa Sidhantavāgīśa (Haridasa Sidhantabagisa), the reading of Tūṣṇīgaṁga (Tushniganga) can be found.

Mahābhārata (Kinjawadekar)(3.135.7.)
Mahābhārata Vols. 1-43 (Siddhāntabāgīśa)(3.111.7.)