At the time of Independence, Northeast India consisted of Assam and the princely states of Manipur and Tripura. Nagaland, Meghalaya, Arunachal Pradesh, and Mizoram were carved out from the large territory of Assam between 1963 and 1987. The separate states were created based on history and the cultural identities of people living in these units.

Assam and Mizoram share a boundary of about 165 km. The border districts in Mizoram are Aizawl, Kolasib and Mamit while in Assam they are Cachar, Karimganj and Hailakandi.