Niger Delta

===Post-colonial period===
In 1961, another major crisis occurred when the then eastern region of Nigeria allowed present-day southwestern [[Cameroon]] to separate from Nigeria (from the region of what is now [[Akwa Ibom State|Akwa Ibom]] and Cross River states) through a plebiscite while the leadership of the Northern Region took the necessary steps to keep northwestern Cameroon in Nigeria, in present-day [[Adamawa State|Adamawa]] and [[Taraba State|Taraba]] states. The aftermath of the [[1961 British Cameroons referendum|1961 plebiscite]] has led to a dispute between Cameroon and Nigeria over the small territory of [[Bakassi]].

A new phase of the struggle saw the declaration of an Independent Niger Delta Republic by [[Isaac Adaka Boro]] during Nigerian president Ironsi's administration, just before the [[Nigerian Civil War]]. Also just before the Nigerian civil war, Southeastern State of Nigeria was created (also known as [[Southeastern Nigeria]] or Coastal Southeastern Nigeria), which had the colonial Calabar division, and colonial [[Ogoja]] division. [[Rivers State]] was also created. Southeastern State and River State became two states for the minorities of the old eastern region, and the majority Igbo of the old eastern region had a state called East Central state. Southeastern State was renamed Cross River State and was later split into [[Cross River State]] and Akwa Ibom State. Rivers State was later divided into Rivers State and Bayelsa State.