States of the Federation and the Federal Capital Territory, Abuja
Section 3(2) · 1999 Constitution (2004 edition)
What Constitution says
(2) Each state of Nigeria, named in the first column of Part I of the First Schedule to this Constitution, shall consist of the area shown opposite thereto in the second column of that Schedule.
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