Tripura is surrounded on three sides by Bangladesh, but its fate wasn't decided by geography. It was sealed in 1947 by a widowed queen facing a rumored invasion.
Unlike British-ruled provinces like Bengal or Punjab, which were sliced in half by the Radcliffe Line based on religious demographics, Tripura was a sovereign princely state. Ruled for centuries by the Hindu Manikya dynasty, its leaders were given the sole authority under the rules of Partition to join either India or Pakistan.
The decision was vastly complicated by geography. Before 1947, the Kingdom of Tripura consisted of two main parts: the sovereign, tribal-dominated hills known as Hill Tipperah, and Chakla Roshnabad, a massive, fertile plains estate in East Bengal. The Maharaja owned Chakla Roshnabad as a zamindar (landlord) under the British, and it served as the economic engine of his kingdom. When the borders were drawn, Chakla Roshnabad was allocated to East Pakistan, but the princely state of Hill Tipperah remained entirely in the hands of the royal family.
Joining Pakistan would have presented an irreconcilable ideological conflict for the Manikyas. The royals were devout Hindus who claimed descent from the Lunar Dynasty of the Mahabharata. They were deeply aligned with mainland Indian culture and were great patrons of Bengali Hindu arts, famously maintaining a close friendship with the poet Rabindranath Tagore.
That queen was Maharani Kanchan Prabha Devi, who took charge as regent after her husband, Maharaja Bir Bikram Kishore Manikya, died unexpectedly in May 1947. Left to manage a highly vulnerable state just months before independence, she faced rumors of a political conspiracy to overthrow the monarchy and forcibly annex Tripura into East Pakistan. In response, she sought assistance from Indian Home Minister Vallabhbhai Patel and signed the Instrument of Accession on August 13, 1947, securing military protection and legally integrating Tripura into India.
After Partition, Tripura's demographics shifted drastically. Hundreds of thousands of Bengali Hindus fled persecution in East Pakistan and poured into Tripura, permanently altering the state's ethnic makeup and cementing its integration into the Indian republic.