The history of the district has proved the fact that earlier East Sikkim was a part of the kingdom of Sikkim. In the 19th century, the district was controlled by the Bhutanese. After the Anglo Bhutan War, the territory was went into the hands of the British forces. When India got its independence in the year 1947, at that time the area was a part of the kingdom of Sikkim under the protection of India. In 1962 Sino-Indian War broke out, which the Nathula Pass witnessed a few skirmishes between India and China. In the year 1975, the Sikkim formally became a part of the Indian Union as its 22th state. For a long period of 30 years, the district was under the rule of the Nepalese in the 18th and 19th centuries.

Mahananda Poudyal, an illustrious Indian writer, social worker and political thinker who wrote a number of short stories, essays, travelogues and criticisms are written by him was born in the district. Some of his main works are Jhumra Ko Putali (1988), Hamra Kehi Lok Katha (1988), Shakespheare Ka Kehi Natya Katha (1996), Bichar Afnai Chhitiz Tira (1996), Chanda Ra Alankar (1988), Sanobhai, Shree Katha, Fulharu, Patiharu (2002), Bhasha Sahitya Barha Bakhan, etc.

Geographically, the district has a total area of 954 sq. km. and occupies the rank 3rd in State and 580th in India on the basis of the size. It lies at 27031' N latitude, 88075' E longitude and 1650 m altitude. In the year 2019, there was a total 74.71% forest area of total geographical area. It is bounded by North Sikkim, South Sikkim, Bhutan, Darjeeling district and West Bengal. 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 2406.4 mm in the year of 2018-19.

Administration wise, the district is divided into 3 sub-districts, 4 towns and 123 villages. Nepali is its official language. It has administrative headquarters at Gangtok.

Demographically, according to the 2011 census, the district has a total number of 61,122 households with a total population of 2,83,583 persons comprising 1,51,432 are males and 1,32,151 are females which led it to rank 1st in the state and 573rd in India. The density of population of the district is 297 (persons per sq km). The sex ratio is pegged at 873 (females per 1000 males) while the child ratio stands at 960 (females per 1000 males). The population growth rate during the period 2001-2011 was 15.73% out of which 13.93% were males and 17.86% were females. As per 2011 census the principal language in the district is Nepali with 65.59%. According to 2011 census the major religions in the district are Hindu and Buddhist with 62.74% and 25.55% of the total population. In the year 2017 the number of live births in the district was 4,946 out of which 2,592 were males and 2,352 were females. In the same year the number of deaths in the district was 1,824 out of which 1,047 were males and 719 were females.

The district is mainly dependent on agricultural sector. More than half of their populations are engaged in agriculture in order to earn their livelihood. The GDDP or Gross District Domestic Product during the period 2007-08 was Rs. 1,23,004 lakh at Current Price and Rs. 85,672 lakh at Constant Prices during the period 1999-2000. The NDDP or Net District Domestic Product during the period 2007-08 was Rs. 1,04,514 lakh at Current Price and Rs. 73,413 lakh at Constant Prices during the period 1999-2000. The Per Capita Income or NDDP, at factor cost during the period 2007-08 was Rs. 38,901 at Current Price and Rs. 2,687 at Constant Prices during the period 1999-2000.

Education wise, according to 2011 census, the literacy rate in the district is 83.85% out of which 88.47% are males and 78.5% are females. The total literate population of the district is 2,14,329 including 1,21,345 are males and 92,984 are females. The total number of illiterates in the district is 69,254 including 30,087 are males and 39,167 are females. Some of the most reputed educational institutions are Damber Singh College, Government College, Sikkim Government College, Sikkim Manipal College of Nursing, District Institute of Education & Training, Advanced technical institute training centre, Sikkim Government Law College, Government Sr. Secondary School, St. Xavier’s School, Taktse International School, SIR T N Senior Secondary School, Mount Zion School, West Point Senior Secondary School, KV NHPC Singtam and Enchey Senior Secondary School.

Kazi Lhendup Dorjee or Kazi Lhendup Dorji or Kazi Lhendup Dorji Khangsarpa or Kazi Saab, had honor to be the first chief minister of Sikkim from 1974 to 1979. Dorjee was the founder and the first President of the Sikkim Praja Mandal. He served as the President of the Sikkim State Congress from the year 1953 to 1958. He also assisted to establish the Sikkim National Congress political party. He was also awarded with the Padma Vibhushan in 2002 and the Sikkim Ratan in 2004. Nakul Das Rai belongs to the Sikkim Democratic Front (SDF) political party. He was also elected as the representative of the Sikkim constituency in the 14th Lok Sabha.

The district has a number of famous and beautiful tourist places which are not only famous within the country but also in the world. Some of the notable places of interest in the district are Gangtok, Aritar, Rumtek, Changu Lake, Nathula, Jurassic Park, Rakdong Tinten, Assam Lingzey to Khedi Trek Route, Village Tourism, Tumin, Banjhakri Falls, Khangchendzonga Tourist Villa. Every year a number of tourists from the worldwide visit this region in order to enjoy its mesmerizing natural sceneries.