Formation of Northeastern States: Years & Timeline After 1947 The formation of Northeastern states took place through several different political and constitutional processes after 1947. Assam continued from an existing province; Nagaland and Meghalaya emerged through reorganisation of Assam; Manipur and Tripura moved from princely-state backgrounds through central administration and Union Territory status; Mizoram and Arunachal Pradesh became Union Territories before attaining statehood; and Sikkim followed a separate path from monarchy and protectorate to an Indian state. For this reason, the formation year of a Northeastern state cannot always be represented accurately by one unexplained date. An accession agreement, administrative merger, autonomous arrangement, Union Territory designation and full statehood are different events. This comparative guide covers all eight states of Northeast India and separates those stages into a state-wise table, a chronological timelin...