Undivided Assam
Undivided Assam refers to the then undivided greater state of Assam in India soon after the Indian Independence in 1947 until 1963. In addition to the present-day Assam, it included the current states of Arunachal Pradesh, Meghalaya, Nagaland and Mizoram. The capital of this state was Shillong, currently the capital of Meghalaya.
Prior to the Partition of India, Sylhet was a part of Assam.
Undivided Assam had a total area of which is slightly smaller than the nation of Ghana. The present day population of Undivided Assam will be 50 million which is slightly less than the population of South Korea.
Present day
After the partition, Undivided Assam was carved into following states:| Date | State/UT | Country | Note |
| 15 Aug 1947 | Sylhet |  Bangladesh | Merged with East Pakistan after partition |
| 15 Aug 1947 | Assam |  India | Became states of Republic of India |
| 1 Dec 1963 | Nagaland | India | Became states of Republic of India |
| 2 Apr 1970 | Meghalaya | India | Became states of Republic of India |
| 21 Jan 1972 | Mizoram | India | Became states of Republic of India |
| 21 Jan 1972 | Arunachal Pradesh | India | Became states of Republic of India |