Siliguri Corridor in the context of "Eastern India"

Bangladesh, officially the People's Republic of Bangladesh, is a country in South Asia. It is the eighth-most populous country in the world and among the most densely populated with a population of over 171 million within an area of 148,460 square kilometres (57,320 sq mi). Bangladesh shares land borders with India to the north, west, and east, and Myanmar to the southeast. It has a coastline along the Bay of Bengal to its south and is separated from Bhutan and Nepal by the Siliguri Corridor, and from China by the Indian state of Sikkim to its north. Dhaka, the capital and largest city, is the nation's political, financial, and cultural centre. Chittagong is the second-largest city and the busiest port of the country.

The territory of modern Bangladesh was a stronghold of many Hindu and Buddhist dynasties in ancient history. Following the Muslim conquest in 1204, the region saw Sultanate and Mughal rule. During the Mughal period, particularly under the Bengal Subah, the region emerged as one of the most prosperous and commercially active parts of the world, known for its thriving textile industry and agricultural productivity. The Battle of Plassey in 1757 marked the beginning of British colonial rule for the following two centuries. In the aftermath of the Partition of India in 1947, East Bengal became the eastern and most populous wing of the newly formed Dominion of Pakistan and was later renamed to East Pakistan.

Nepal, officially the Federal Democratic Republic of Nepal, is a landlocked country in South Asia. It is mainly situated in the Himalayas, but also includes parts of the Indo-Gangetic Plain. It borders the Tibet Autonomous Region of China to the north, and India to the south, east, and west, while it is narrowly separated from Bangladesh by the Siliguri Corridor, and from Bhutan by the Indian state of Sikkim. Nepal has a diverse geography, including fertile plains, subalpine forested hills, and eight of the world's ten highest mountains, including Mount Everest, the highest point above mean sea level on Earth. Kathmandu is the nation's capital and its largest city. Nepal is a multi-ethnic, multi-lingual, multi-religious, and multi-cultural state, with Nepali as the official language.

The name "Nepal" is first recorded in texts from the Vedic period of the Indian subcontinent, the era in ancient Nepal when Hinduism was founded, the predominant religion of the country. In the middle of the first millennium BC, Gautama Buddha, the founder of Buddhism, was born in Lumbini in southern Nepal. Parts of northern Nepal were intertwined with the culture of Tibet. The centrally located Kathmandu Valley is intertwined with the culture of Indo-Aryans, and was the seat of the prosperous Newar confederacy known as Nepal Mandala. The Himalayan branch of the ancient Silk Road was dominated by the valley's traders. The cosmopolitan region developed distinct traditional art and architecture. By the 18th century, the Gorkha Kingdom achieved the unification of Nepal. The Shah dynasty established the Kingdom of Nepal and later formed an alliance with the British Empire, under its Rana dynasty of premiers. The country was never colonised but served as a buffer state between Imperial China and British India. Parliamentary democracy was introduced in 1951 but was twice suspended by Nepalese monarchs, in 1960 and 2005. The Nepalese Civil War in the 1990s and early 2000s resulted in the establishment of a secular republic in 2008, ending the world's last Hindu monarchy. The Constitution of Nepal, adopted in 2015, affirms the country as a federal parliamentary republic divided into seven provinces. In September 2025, protests against a social media ban and economic inequality caused riots, resulting in casualties and resignation of the prime minister.

Assam is a state in northeastern India, south of the eastern Himalayas along the Brahmaputra and Barak River valleys. Assam covers an area of 78,438 km (30,285 sq mi). It is the second largest state in northeastern India by area and the largest in terms of population, with more than 31 million inhabitants. The state is bordered by Bhutan and Arunachal Pradesh to the north; Nagaland and Manipur to the east; Meghalaya, Tripura, Mizoram and Bangladesh to the south; and West Bengal to the west via the Siliguri Corridor, a 22-kilometre-wide (14 mi) strip of land that connects the state to the rest of India. Assamese and Bodo are two of the official languages for the entire state and Meitei (Manipuri) is recognised as an additional official language in three districts of Barak Valley and Hojai district. in Hojai district and for the Barak Valley region, alongside Bengali, which is also an official language in the Barak Valley.

The state has 35 districts with 5 divisions. Guwahati (containing the state capital Dispur) is the largest city in northeastern India. Assam is known for Assam tea and Assam silk. The state was the first site for oil drilling in Asia. Assam is home to the one-horned Indian rhinoceros, along with the wild water buffalo, pygmy hog, tiger and various species of Asiatic birds, and provides one of the last wild habitats for the Asian elephant. The Assamese economy is aided by wildlife tourism to Kaziranga National Park and Manas National Park, which are World Heritage Sites. Dibru-Saikhowa National Park is famed for its feral horses. Sal tree forests are found in the state which, as a result of abundant rainfall, look green all year round. Assam receives more rainfall than most parts of India; this rain feeds the Brahmaputra River, whose tributaries and oxbow lakes provide the region with a distinctive hydro-geomorphic environment.

Northeast India, officially the North Eastern Region (NER), is the easternmost region of India representing both a geographic and political administrative division of the country. It comprises eight states: Arunachal Pradesh, Assam, Manipur, Meghalaya, Mizoram, Nagaland, and Tripura (commonly known as the "Seven Sisters"), and the "Brother" state of Sikkim. North-east India is one of the most linguistically diverse regions in the world.

The region has India's international border of 5,182 kilometres (3,220 mi) with five neighbouring countries: China to the north, Myanmar to the east, Bangladesh to the southwest, Nepal to the west, and Bhutan to the northwest. It comprises an area of 262,184 square kilometres (101,230 sq mi), almost 8 per cent of that of India and has a population of 45,772,188, almost 4 per cent that of India. The Siliguri Corridor connects the region to other parts of India.

Sikkim (/ˈsɪkɪm/ SIK-im; Nepali: [ˈsikːim]) is a state in northeastern India. It borders Bhutan in the east, the Tibet Autonomous Region of China in the north and northeast, Koshi Province of Nepal in the west, and West Bengal in the south. Sikkim is also close to the Siliguri Corridor, which borders Bangladesh. Sikkim is the least populous and second-smallest among the Indian states. Situated in the Eastern Himalaya, Sikkim is notable for its biodiversity, including alpine and subtropical climates, as well as being a host to Kangchenjunga, the highest peak in India and third-highest on Earth. Sikkim's capital and largest city is Gangtok. Almost 35% of the state is covered by Khangchendzonga National Park – a UNESCO World Heritage Site.

The Kingdom of Sikkim was founded by the Namgyal dynasty in the 17th century. It was ruled by Buddhist priest-kings known as the Chogyal. It became a princely state of the British Indian Empire in 1890. Following Indian independence, Sikkim continued its protectorate status with the Union of India after 1947 and the Republic of India after 1950. It enjoyed the highest literacy rate and per capita income among Himalayan states. In 1973, anti-royalist riots took place in front of the Chogyal's palace. In 1975, after the Indian Army took over the city of Gangtok, a referendum was held that led to the dissolution of the monarchy and Sikkim's joining India as its 22nd state.

Nepal measures about 880 kilometers (547 mi) along its Himalayan axis by 150 to 250 kilometers (93 to 155 mi) across. It has an area of 147,516 km (56,956 sq mi).

Nepal is landlocked by China's Tibet Autonomous Region to the north and India on other three sides. West Bengal's narrow Siliguri Corridor separate Nepal and Bangladesh. To the east are Bhutan and India.