The Federal Military Government of Nigeria abolished the four regions in 1966, following the first military coup that occurred in January 1966. Here’s what happened:

• Before 1966, Nigeria was divided into four regions:

  • Northern Region

  • Western Region

  • Eastern Region

  • Mid-Western Region

• After the coup, Major General Johnson Aguiyi-Ironsi came to power and introduced the Unification Decree No. 34 of 1966, which abolished the federal structure and replaced the regions with a unitary system of government.

• Although the regional structure was formally dismantled, state creation began later under General Yakubu Gowon in 1967, when Nigeria was restructured into 12 states—a move largely intended to weaken the secessionist strength of the Eastern Region during the Biafran crisis.