The nearby area of the Kameng river at various points of time went into the hands of the Mon kingdoms, Tibet and the Ahom kingdom. Whenever there was no major political powers dominated the area at that time Aka and Nishi chiefs controlled it. In 1965 the then Kameng Frontier division was renamed as the Kameng district. After sometime the Political Officer was also re-designated as the Deputy Commissioner of Kameng. However, due to some significant political reasons, the Kameng district was divided into two parts likewise East Kameng and West Kameng on 1st June, 1980. when it comes to the composition of the people and its history, one important fact can be mentioned that earlier the district was predominantly inhabited by the Scheduled Tribes of Arunachal Pradesh. At present the Bangnis and Sulungs are the major tribes of the district. The history of all these tribes including their migration, material and socio-cultural and other allied aspects all are very interesting.

Geographically, the district has a total area of 11,556 sq. km. area and occupies the rank 3rd in State and 41th in India on the bases of this size. It lies at 27°42'N latitude, 93°02'E longitude and 363 m altitude. In the year 2021, there was a total 88.48% forest area of the total geographical area. The district is bounded by Tibet in the North, Sonitpur District of Assam in the South, Kurung Kumey District of Arunachal Pradesh, in the North East, Papumpare District of Arunachal Pradesh in the North West and West Kameng District of Arunachal Pradesh in the West. Kameng River, Pacha, Pachi, Pachuk, Papu-para, Pakke, Bishom, Dibru are major rivers of the district. The climate of the district remains pleasant almost throughout the year. Most of its rainfall occurs in the monsoon season. The actual rainfall in the district was 2304.6 mm in the year of 2021-22.

The district has 13 sub-districts, 1 town and 382 villages. English is its administrative language. The district came into existence on 1st June, 1980. It has administrative headquarters located at Seppa Town which is situated at the distance of 226 kms from the State Capital. The district comprises 2 sub-divisions namely Seppa and Chayangtajo, which are further divided into 13 administrative circles such as Chayangtajo, Sawa, Khenewa, Bameng, Lada, Gyawe Purang, Pipu, Seppa, Richukhrong, Pijirang, Pakke-Kessang, Seijosa and Dissing Passo. There are total 5 legislative assembly constituencies in the district are Bameng, Chayangtajo, Seppa East, Seppa West and Pakke-Kasang. All of these are the part of Arunachal West Lok Sabha constituency.

Demographically, according to the 2011 census, the district has a total number of 14,610 households with a total population of 78,690 comprising 38,775 are males and 39,915 are females which leads it to rank 8th in the state and 621 in India. The density of population of the district is 19 (persons per sq km.). The sex ratio is pegged at 1029 (females per 1000 males) while the child ratio stands at 1001 (females per 1000 males). The schedule tribe population of the district is recorded as 72,400 including 35,266 are males, and 37,134 are females. The percentage of Schedule Tribe is 7.61%. As per 2011 census the percentage of major religions practiced by the people of this region are Christian 47.19% and Hindu with 15.67% of the total population. The population growth rate during the period of 2001-2011 was 37.62% including 34.63% were males and 40.66% were females. According to 2011 census the principal language in the district is Nissi/Dafla with 83.03%. In the year 2020 the number of live births in the district was 2,158 out of which 1,052 were males and 1,106 were females. In the same year the number of deaths in the district was 146 out of which 107 were males and 39 were females.

Economically, the district is dependent on agriculture primarily. Rice, barley, apples, oranges, millet, chilly, vegetables, sweet-potato, pine apple, banana, guava are mainly produced here. Fishery is the prime Industry of the region. The district is known for its orchards. Mainly Jhum cultivation is in practice in the region. In the year 2021-22 the gross domestic product in the district was Rs. 1,36,159 lakhs at current price and Rs. 80,702 lakhs at constant prices in the year 2011-2012. The net domestic product in the district during the period 2021-22 was Rs. 1,24,722 lakh at current price and Rs. 72,030 lakh at constant prices in the year 2011-2012. The Per Capita Income or NDDP, At Factor Cost during the period 2021-22 was Rs. 1,44,429 at current price and Rs. 83,411 at constant prices in the year 2011-2012.

Education wise, according to the 2011 census, the literacy rate in the district is 60.02% including 68.65% are males and 51.69% are females. The total literate population in the district is 38,449 out of which 21,599 are males and 21,599 are females. The total number of illiterates in the district is 40,241 out of which 17,176 are males and 23,065 are females. Government Higher Secondary School, Government College, District Institute of Education and Training (DIET) are some of the educational institutions in the district.

Tani Loffa is the member of the Bhartiya Janata Party. In the year 2004, he became the member of assembly constituency of Arunachal Pradesh. Nyari Welly was the first woman elected to the Arunachal Pradesh Legislative Assembly.

The district has some historical and religious places to visit which are famous worldwide. These places are Bameg Top View, Kameng River, View of Lumdung (Pappu Valley).Pakke-Valley, Passa Valley, Bameng, Chayangtajo, Pakke-Kessang. Pakhui Tiger Reserve is the most famous tourist spots at East Kameng district. There are three major hill stations of East Kameng district-Bameng, Chayangtajo and Pakke-Kessang. 'Gorichen' in Chayangtajo is the snow peaked Mountain. During the winter season, Kameng River is a good spot for angling and fishing in winter season.