States of the Federation and the Federal Capital Territory, Abuja
Section 3(3) · 1999 Constitution (2004 edition)
What Constitution says
(3) The headquarters of the Governor of each State shall be known as the Capital City of that State as shown in the third column of the said Part I of the First Schedule opposite the State named in the first column thereof.
This is the 1999 Constitution as published in 2004. Later amendments aren't included yet, so a section may have changed since.
Original source
Official Gazette · CFRN 1999 official PDF · printed page 17. Original document
Release: draft-c8d50d87fae9. Source scope, review and corrections