[web 1] Sonowal was a multicaste 'khel' (guild) of the many khels that existed in the Ahom Kingdom of the late medieval[3] period.
This khel was involved in the gold-washing business and it consisted paiks from different communities viz, Kacharis, Bihiyas (Chutias),[4][5] Koch, Miri (Mising), Dafla (Nyishi) and Keot.
Most of these Sonowals migrated from Sadiya and Sisi-Dhemaji regions respectively and resided in the forested area between the Buri Dihing and Dibru rivers (Matak territories) during the early 19th century.
[7] These officers remained in overall charges of these guilds and had to take a note of the total output of such washings conducted under the state initiative.
But as these surnames are common to all Assamese people irrespective of their caste, some frauds were found to take advantage of it in getting ST certificate.