Below is the list of all postal/zip codes of all states in Nigeria.
Abia 440001
Adamawa 640001
Anambra 420001
Akwa Ibom 520001
Bauchi 740001
Bayelsa 560001
Benue 970001
Borno 600001
Cross River 540003
Delta 320001
Ebonyi 840001
Enugu 400001
Edo 300001
Ekiti 360001
Gombe 760001
Imo 460001
Jigawa 720001
Kaduna 800001
Kano 700001
Katsina 820001
Kebbi 860001
Kogi 260001
Kwara 240001
Lagos (Island) 101001
Lagos (Mainland) 100001
Nasarawa 950001
Niger 920001
Ogun 110001
Ondo 340001
Osun 230001
Oyo 200001
Plateau 930001
Rivers 500001
Sokoto 840001
Taraba 660001
Yobe 320001
Zamfara 880001
Source:
http://nigeriapostalzipcodes.com.ng/postal-codes-nigeria-states/