Section 2 & 3 of the 1999 Constitution of the Federal Republic of Nigeria
2 (1) Nigeria is one indivisible and indissoluble Sovereign State to be known by the name of the Federal Republic of Nigeria
(2) Nigeria shall be a Federation consisting of States and a Federal Capital Territory.
3.(1) There shall be thirty six States in Nigeria, that is to say, Abia, Adamawa, Awa Ibom, Anambra, Bauchi, Bayelsa, Benue, Borno, Cross River, Delta, Ebonyi, Edo, Ekiti, Enugu, Gomb, Imo, Jigawa, Kaduna, Kano, Katsina, Kebbi, Kogi, Kwara, Lagos, Nasarawa, Niger, Ogun, Ondo, Osun, Oyo, Plateau, Rivers, Sokoto, Taraba, Yobe and Zamfara.
(2) Each State of Nigeria named in the first column of Part 1 of the First Schedule to this Constitution shall consist of the area shown opposite thereto in the second column of that Schedule.
(3) The headquarters of the Government of each State shall be known as the Capital City of that State as shown in the third column of the said Part 1 of the First Schedule opposite the State named in the first column thereof.
(4) The Federal Capital Territory, Abuja shall be as defined in Part II of the First Schedule to this Constitution.
(5) The provision of this Constitution in Part 1 of Chapter VIII hereof shall, in relation to the Federal Capital Territory, Abuja, have effect in the manner set out thereunder.
(6) There shall be seven hundred and sixty-eight local government areas in Nigeria as shown in the second column of Part I of the First Schedule to this Constitution and six area councils as shown in Part I of that Schedule.