SouthEastern States Of Nigeria:

According to: https://en.wikipedia.org/wiki/Geopolitical_zones_in_Nigeria
South East (Nigeria): loosely known as former East-Central State of Abia State, Anambra State, Ebonyi State,
Enugu State and Imo State


Igboland:

Igboland (Standard Igbo: Àlà Ị̀gbò), also known as Southeastern Nigeria and formerly known as Ibo or Iboland,[3] is a non-governmental cultural region and a linguistic area in Nigeria that is defined by the Igbo culture and language. It is primarily situated in the Lowland forest region of Nigeria, with minor parts in the Niger-Delta, where the Niger river fans out into the atlantic ocean in a vast network of creeks and mangrove swamps on the Bight of Bonny located between latitude 5–7 degrees north and longitude 6–8 degrees east, and occupies a total landmass of about 16,000 square miles in southern Nigeria.[4] It has lands on both sides of the lower Niger River, although the larger chunk of the region is situated on the east of the river. The region is surrounded by a host of large rivers. Igboland's culture has been shaped by its rainforest climate. As this area constitutes a large part of the south-eastern part of Nigeria, it is often referred to as the 'The East' locally. The majority of the Igbo-speaking population in Igboland identify as ethnic Igbo.


https://en.wikipedia.org/wiki/Igboland


Biafra:

The Eastern Region was one of Nigeria's federal divisions, dating back originally from the division of the colony Southern Nigeria in 1954. Its first capital was Calabar. The capital was later moved to Enugu and the second capital was Umuahia. The region was officially divided in 1967 into three new states,in the East-Central State, Rivers State and South-Eastern State. East-Central State had its capital at Enugu, which is now part of Enugu State.

The Region had the third, fourth and the fifth largest ethnic groups in the country[b] Igbo, Ibibio, and Ijaw[/b] next to Hausa/Fulani and Yoruba. The then Eastern Region failed to capitalize on this but rather engaged in in-fighting and the wrong labeling of Ibibio and Ijaw as minority ethnic groups.

The region was what later became "Biafra", which was in rebellion from 1967 to 1970.