East Sikkim is one of the four administrative districts of the Indian state of Sikkim. Geographically, East Sikkim occupies the south-east corner of the state. The headquarter of East Sikkim is Gangtok, which is also the state capital. It is the hub of all administrative activity in the state. The district is surrounded by Kalimpong district of West Bengal in the South and South East, Bhutan in the East, People’s Republic of China in the North East, North Sikkim district in the North and South Sikkim district in the West.

Gangtok is a city, municipality, the capital and the largest town of the Indian state of Sikkim. It is also the headquarters of the East Sikkim district. Gangtok is in the eastern Himalayan range, at an elevation of 1,650 m (5,410 ft). The town’s population of 100,000 are from different ethnicities such as Bhutia, Lepchas and Indian Gorkhas. Within the higher peaks of the Himalaya and with a year-round mild temperate climate, Gangtok is at the centre of Sikkim’s tourism industry.

Tsomgo Lake, also known as Tsongmo Lake or Changgu Lake, is a glacial lake in the East Sikkim district of the Indian state of Sikkim, some 40 kilometres (25 mi) from the capital Gangtok. Located at an elevation of 3,753 m (12,313 ft), the lake remains frozen during the winter season. The lake surface reflects different colours with change of seasons and is held in great reverence by the local Sikkimese people. Buddhist monks prognosticated after studying the changing colours of the lake.

Nathu La is a mountain pass in the Himalayas in East Sikkim district. It connects the Indian state of Sikkim with Tibet. The pass, at 4,310 m above mean sea level, forms a part of an offshoot of the ancient Tea Horse Road. Nathu means “listening ears” and La means “pass” in Tibetan.