Other large South-South cities include (in descending order by population) Warri/Uvwie, Calabar, Uyo, Ikot Ekpene, Ugep, Sapele, Buguma, Uromi, Ughelli, Ikom, and Asaba.

Edo, Delta, one-quarter of Bayelsa, and the Ndoni section of Rivers states were from the old Western region.

Unlike the development authorities of other zones like the North-East Development Commission, the present authorities are responsible for the areas outside of the South-South as the NDDC was created in response to protests and conflict in the wider Niger Delta region.

However, PDP margins of victory decreased in 2019, when Atiku Abubakar was the party nominee.

In 2023, with Abubakar again as the PDP nominee, four South-South states broke their streaks of PDP voting — with Rivers being won by Bola Tinubu (APC) amid widespread irregularities while Cross River, Delta, and Edo voted for Peter Obi (LP).