<Ul> <Li> Assamese </Li> <Li> Bengali </Li> <Li> Bodo </Li> <Li> Garo </Li> <Li> Khasi </Li> <Li> Kokborok </Li> <Li> Nyishi </Li> <Li> Galo </Li> <Li> Adi </Li> <Li> Meitei </Li> <Li> Gorkhali </Li> <Li> Hindi </Li> <Li> English </Li> </Ul> <P> Northeast India (officially 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, Sikkim and Tripura . The Siliguri Corridor in West Bengal, with a width of 21 to 40 kilometres (13 to 25 mi), connects the North Eastern Region with East India . The region shares more than 4,500 kilometres (2,800 mi) of international border with Tibet Autonomous Region, China in the north, Myanmar in the east, Bangladesh in the southwest and Bhutan to the northwest . It comprises an area of 262,230 square kilometres (101,250 sq mi), almost 8 percent of that of India, and is one of the largest salient (panhandle) in the world . </P> <P> The states of North Eastern Region are officially recognised under the North Eastern Council (NEC), constituted in 1971 as the acting agency for the development of the north eastern states . Long after induction of NEC, Sikkim formed part of the North Eastern Region as the eighth state in 2002 . India's Look - East connectivity projects connect Northeast India to China and ASEAN . </P> <P> The earliest settlers may have been Austro - Asiatic speakers from Southeast Asia, followed by Tibeto - Burmese from China and by 500 B.C. Indo - Aryans speakers from Gangetic Plains . Due to the bio - and crop diversity of the region, archaeological researchers believe that early settlers of Northeast India had domesticated several important plants . Writers believe that the 100 BC writings of Chinese explorer, Zhang Qian indicate an early trade route via Northeast India . The Periplus of the Erythraean Sea mention a people called Sêsatai in the region, who produced malabathron, so prized in the old world . </P>

When did sikkim became a part of north east india