The Upper Subansiri district is named after the mighty Subansiri River which meanders through the entire territory of the district. In 1914, the district was the part of Western Section of North-East Frontier Tract, later renamed as Balipara Frontier Tract in 1919. The tract was divided into Se LA Sub-Agency and Subansiri Area in 1946. The Subansiri Frontier Division was renamed as Subansiri District in the year 1965. In 1987, it was divided into two parts and one of it is called Upper Subansiri District. Three major tribes inhabit the Upper Subansiri District from the very beginning are the Tagin, the Nyishi, and the Galo. There is a close co-relation among these three tribes so far as their socio-economic aspects are concerned.

Tapi Mra, the first India mountaineer to climb Everest was born in the district. He has also climbed Island Peak in 2007, Mera Peak in 2008, Mount Everest in 2009, Uhuru Peak of Mount Kilimanjaro in 2010 and Mount Kosciuszko in 2011.

Geographically, the district has a total area of 8,325 sq. km. and occupies the rank 9th in State and 97th in India on the basis of the size. It lies at 27°79'N latitude, 94°34'E longitude and 600 m altitude. In the year 2021, there was a total 79.08% forest area of total geographical area. The district is bounded by Tibet in the North, West Siang District and Lower Subansiri District of Arunachal Pradesh in the South, West Siang District of Arunachal Pradesh in the East, Lower Subansiri District of Arunachal Pradesh in the South West and Kurung Kumey District in the North West. The principal rivers that flow through the district are Subansiri and Sigin. 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 1211.9 mm in the year of 2021-22.

Administratively, the district is divided into 15 sub-districts, 1 town and 553 villages. English is its administrative language. The district came into existence in the year 1987. It has administrative headquarters located at Daporijo Town, situated at the distance of 271 kms from the State Capital. There are total 5 legislative assembly constituencies in the district namely Nacho, Taliha, Daporijo, Raga, and Dumporijo. 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 15,541 households with a total population of 83,448 comprising 41,758 are males and 41,690 are females which leads it to rank 9th in the state and 622 in India. The density of population of the district is 14 (persons per sq km.). The sex ratio is pegged at 998 (females per 1000 males) while the child ratio stands at 970 (females per 1000 males). As per 2011 census the major religions practiced by the people in the district are Hindu and Christian with 16.15% and 10.52% of the total population. The population growth rate during the period of 2001-2011 was 50.78% including 47.87% were males and 53.8% were females. According to 2011 census the principal languages in the district are Nissi/Dafla and Adi with 78.71% and 14.95%. In the year 2020 the number of live births in the district was 1,075 out of which 477 were males and 598 were females. In the same year the number of deaths in the district was 58 out of which 48 were males and 10 were females.

Economically, the district is mainly dependent on the agricultural sector. The district is considered as one of the most backward districts and currently receiving funds from the Backward Regions Grant Fund Programme. The chief agricultural products in the district are paddy, millet, maize, potato, mustard, soya bean, sugarcane, ginger, etc. Natives of the place earn their extra income from some horticulture products like apple, walnut, citrus, kiwi, pineapple, banana, etc. The district has a huge deposit of coal mineral resources. In the year 2021-22 the gross domestic product in the district was Rs. 1,24,126 lakhs at current price and Rs. 73,723 lakhs at constant prices in the year 2011-2012. The net domestic product in the district during the period 2021-22 was Rs. 1,12,474 lakh at current price and Rs. 64,861 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. 1,66,544 at current price and Rs. 96,042 at constant prices in the year 2011-2012.

Education wise, according to the 2011 census, the literacy rate in the district is 63.8% including 70.02% are males and 57.59% are females. The total literate population in the district is 45,278 out of which 24,807 are males and 20,471 are females. The total number of illiterates in the district is 38,170 out of which 16,951 are males and 21,219 are females. Government Higher Secondary School, Jawahar Navodaya Vidyalaya, Vivekananda Kendra Vidyalaya, Si-Donyi Public school, etc are some of the most reputed educational institutions in the district.

Tapen Siga, a veteran Indian politician and a member of the Bharatiya Janata Party is currently serving as the member of the Arunachal Pradesh Assembly.

The district has some historical and religious places which are not only famous within the country but also in the world. Some of its notable places of interest are Rock Cave Temple, He Rugged Mountains with rocky tops, snow clad mountain, a hub for the tourist, beautiful natural lake.