The divisions of the Igbo world

Forde & Jones call this "Eastern or Cross River Ibo" and place it in north-east Bende Division and south-east Okigwi Division, in Afikpo Division and in Arochuku Division. It contains the Ada (Edda), Abam (Ohaffia) and Aro groups, and the survey treats it as the division in which non-Igbo elements are most prominent. Also called Aro, after Arochukwu.

Forde & Jones call this "North-Eastern Ibo (Ogu Uku)" — Ogu Uku being the name of the large hoe used there — and place it in Ogoja Province, Abakaliki Division and the part of Afikpo Division north of the Asu river. The survey treats the whole division as a single group dominated by three large tribes, Ezza, Ikwo and Izi, which the administration called clans, with smaller communities related to the Ezza in north Afikpo Division. Also called Ogu Ukwu, after the hoe used there.

Forde & Jones call this "Northern or Onitsha Ibo". It covers Onitsha Province and the northern part of Okigwi Division in Owerri Province, and is the source's line between the Igbo of the northern uplands and the Southern Ibo to the south. The survey divides it into a Western or Nri-Awka group, an Eastern or Elugu group and Onitsha Town; Afigbo keeps that split and adds the adjoining Agbaja as a third sub-cultural group, while treating all such delimitations as approximate. Also called Wawaa.

The riverine Igbo call themselves Oru, and the adage Oru na Igbo bu ofu — Oru and Igbo are one — is how they place themselves: Igbo, with a way of life of their own. Their towns run along the Niger and up its great tributaries, the Orashi and the Omambala, and they built their settlements on the water's edge where the interior Igbo avoided it — compact towns at the riverbank, fishing, canoe-building and trade. Oguta, Aboh, Anam and Ogbaru grew into the trading centres of the lower Niger, dealing with the Igala, the Edo and the Izon as well as with Igbo towns, and the Oru fed much of Igboland from their farms and their waters. They developed kingship earlier and further than most Igbo societies — an Obi or Ezeigwe with a council of Ndiche and Ndiokpara to balance him — and Oru titles such as Iyase-Onowu, Onise and Odogwu passed into Igbo political life more widely. Oru is not one descent group: it is proto-Igbo peoples who moved east and took to the water, and their towns are found on both banks and down into the creeks as far as Sagbama, Mbiama, Nembe and Odioma. The names Ogbashu and Ozizor are still used among them for those who paddle downriver and those who go up against it.

Forde & Jones call this "Southern or Owerri Ibo". It covers Owerri Province — the Okigwi, Owerri, Ahoada, Aba and Bende Divisions — and is split into the Isu-Ama, Oratta-Ikwerri, Ohuhu-Ngwa and Isu-Item groups. Also called Isu-Urata.

The Igbo west of the Niger and along its flood plain, in the Ogwashi Uku District of Benin Province, Kwale Division of Warri Province, the Onitsha Division of Onitsha Province and the Ahoada Division of Rivers Province. The survey divides it into Northern Ika, Southern Ika or Kwale, and the Riverain Igbo, who call themselves Oru. Also called Anioma. Its three tribes are Ukwuani, Enuani and Ika — the owner's correction: "it is divided into three tribes, which are Ukwuani, Enuani, and Ika". Enuani is the Aniocha and Oshimili country, whose people share one dialect; Ika is the Ika-speaking country of Agbor and Umunede; Ukwuani is the Ndokwa country along the lower Niger.