On the 5th of May,1967, Nigeria's military government, led by General Yakubu Gowon, reorganised the country from its four regions (Northern, Eastern, Western and Mid-Western Regions) into 12 states. This restructuring aimed to address ethnic and political tensions, particularly in response to the growing secessionist movement in the Eastern Region, which later led to the Nigerian Civil War. The 12 states created in 1967 were:

1. North-Western State
2. North-Eastern State
3. Kano State
4. Kaduna State
5. Kwara State
6. Benue-Plateau State
7. Lagos State
8. Western State
9. Mid-Western State
10. East-Central State
11. Rivers State
12. South-Eastern State