What makes West Africa a region

The coast, and the three that do not touch it

The Atlantic edge runs from the Senegal River to the Nigerian delta, and thirteen of the countries filed here hold part of it. Burkina Faso, Mali and Niger do not, and each of the three borders at least one member that does, which is why the corridors carrying their trade run inland from Dakar, Abidjan, Tema, Lomé and Cotonou rather than along the shore.

The Niger River makes the same argument from the other direction. It rises in the Guinea Highlands a short way from the Atlantic, runs northeast into Mali, turns south at the edge of the Sahara, crosses the country that carries its name, forms part of the border with Benin, and reaches the sea through Nigeria. One river, five members, and a route that moved goods between the forest and the desert long before the borders it now crosses were drawn.

One currency, and the rest

Benin, Burkina Faso, Guinea-Bissau, Ivory Coast, Mali, Niger, Senegal and Togo use the West African CFA franc, issued from Dakar by the Central Bank of West African States. Its parity is fixed rather than floating: set against the French franc when the currency was created in December 1945, devalued on 12 January 1994, and converted on 1 January 1999 to 655.957 to the euro, where it has stayed. The others each issue their own, and Liberia's dollar circulates beside the United States dollar.

What the treaty covers, and what it stopped covering

ECOWAS was established by the Treaty of Lagos on 28 May 1975 and sits in Abuja. Twelve of the countries here belong to it. Mauritania gave notice in 1999 and left in December 2000. Burkina Faso, Mali and Niger signed the Charter of Liptako-Gourma establishing the Alliance of Sahel States on 16 September 2023, gave notice of withdrawal in January 2024, and ceased to be members on 29 January 2025, with ECOWAS holding a six-month window open afterwards for the terms of separation. The country pages carry the membership. The region does not move with it, because a region here is a position on the map rather than a list of signatures.

Where the edges are argued

The M49 scheme published by the UN Statistics Division assigns the same countries to Western Africa and adds Saint Helena, which this catalogue files under the South Atlantic instead, the nearest mainland being a very long way off. Cameroon and Chad sit in Middle Africa under M49 and under Central Africa here, and a reader working from a wider definition of West Africa will find them missing.

Mauritania is the case that moves. M49 files it in Western Africa and so does this catalogue. It is also a member of the Arab League and a founding member of the Arab Maghreb Union of 1989, which is the reading that puts it in the Maghreb. Both are on the record, and neither is settled here.

The official languages, and what the records list instead

French is official in Benin, Guinea, Ivory Coast, Senegal and Togo, English in the Gambia, Ghana, Liberia, Nigeria and Sierra Leone, Portuguese in Cape Verde and Guinea-Bissau, and Arabic in Mauritania. Burkina Faso, Mali and Niger name national languages instead: Mooré, Dioula and Bissa; thirteen in Mali's record, from Bambara to Tamasheq; Hausa. Togo carries the detail that fits no pattern, having joined the Commonwealth in June 2022 with no British colonial period behind it.