Jonai is the easternmost sub-division of Dhemaji District, about 554 Km. away from the state capital, Guwahati. Covering a total Geographical area of 1111.81 Sq. Km, it is bounded by Arunachal Pradesh in the north, Lali & Brahmaputra River in the south, Sipiya river & Sadiya Subdivision of Tinsukia district in the east and Simen River in the west. The Head Quarter is located at 95.160 E and 27.770 N.
The Subdivision comprises with one Development Block named by Murkong Selek Tribal Development Block, One Revenue Circle named by Jonai Revenue Circle and 15 Nos. of Gaon Panchayat
General Particulars
| Geographical Area | 1111.81 Sq. Km. | |
| Rural | 1111.81 Sq. Km. | |
| Urban | 0 Sq. Km. | |
| Revenue Circle | 1 No. | |
| Community Development Block | 1 No. | |
| Police Station | 1 No. | |
| Police Out Post | 1 No. | |
| Border Out Post | 4 Nos. | |
| Fire Station | 1 No. | |
| Municipal Board / T. C. | Nil | |
| Gaon Panchayat | 15 Nos. | |
| Anchalik Panchayat | 1 No. | |
| Mouza | 1 No. | |
| Revenue Villages | 242 Nos. | |
| Census Villages (2001 Census) | 381 Nos. |
Population 2001 Census
| Total Population | 143199 Nos. | |
| Male | 74023 Nos. | |
| Female | 69176 Nos. | |
| Density | 127.58 per sq. Km. | |
| Schedule Caste's Population | 3708 Nos. | |
| Male | 1945 Nos. | |
| Female | 1763 Nos. | |
| Schedule Tribes Population | 98977 Nos. | |
| Male | 50686 Nos. | |
| Female | 48291 Nos. | |
| Total Population in the age group 0-6 | 25,944 Nos. | |
| Male | 13,341 Nos. | |
| Female | 12,603 Nos. | |
| Total Literate Population | 69,854 Nos. | |
| Male | 41,506 Nos. | |
| Female | 28,348 Nos. | |
| Revenue Villages | 273 Nos. | |
| Census Villages (2001 Census) | 381 Nos. |