Inscriptions.
Mainly two types of inscriptions are available at Nilachal Hill.The stone and metallic inscriptions. The oldest among that, is the stone epigraph which is a rock inception. This is known as Umachal rock inception of 5th century AD and also regarded as the oldest in North East India. The inscriptions found in Nilachal are mainly documents that were issued for maintenance of the Temple and its renovation, constructions, issuing land grants to the priests etc. Eighteen inscriptions of Nilachal Hill have been translated and documented.