The writings of many authors have brought to light the existence of a route from Bhairabkunda and Udalguri, through Bhutal hills, right upto countries like Afghanistan, China and Tibet. This route was quite significant for the interchange of culture, even though trade was not the actual intention of this route. It was utilized by Tantriks, Buddhist sromons, Yogi and Nath. When this place was invaded by Mohammed Bin Bokhtiar in 1205 A.D., he is said to have used this route in order to gain access to Kamrup. His intention was to invade the countries of Turkistan, Tibet and China. However, just after he crossed Kamrup, Bokhtiar had reached an open region which was located near the hills and where the tribal people resided. As per the records of history, he was defeated at this very place and was compelled to make a retreat.
Raonagar might be the name of this place, which was situated about 13 km from the southern part of the Bhutan hills and 9 km from the western portion of the district of Udalguri. This rampart also finds mention in Padma Purana which was composed by Narayana Deva, who was a renowned poet patronized by the Kochi ruler Dharamayarayana in the period about 1615 A.D to 1637 A.D. In the remote past, Udalguri district was represented by the villages of Niz-Udalguri, Angragaon and Puronithana. The modern-day Udalguri is located on the banks of the rivers like Daisam, Golondi, Khaorong and others. It is said that in the ancient ages, there was hardly any human habitation in the current region of Udalguri. Natural calamities like floods or ailments like Cholera, small pox, etc were also the culprits of a deserted Udalguri district.
Daisam, Kahorong, Golondi and others might have altered their courses several times as they flowed across Udalguri. Swampy areas are existent near Nalbari village and Kathalguri which spread up to Puroni Goraibari village. There was a marsh present here which contained poisonous snakes. Khaorong and Golondi rivers flowed near the modern-day Golma area.
