Places · Biswanath Ghat
Umatumoni Island
A small island in the Brahmaputra off Biswanath Ghat, with an ASI-protected carved rock and an old stone inscription.
The district administration describes Umatumoni (also spelt Umatumuni or Umatamani) as “an archaeologically famous place” that visitors can reach from Biswanath Ghat.
A rock on the island known as Sakreswar is a monument of national importance protected by the Archaeological Survey of India.
According to Wikipedia (unsourced there), a stone inscription found here records the coronation of a king named Lakshminah, whom historians identify with the Chutia king Lakshminarayan.
Ask at the ghat about boats before you go. Crossings depend on the river and the season.