Overview
The Gulf of Guinea is the northeasternmost part of the tropical Atlantic Ocean from Cape Lopez in Gabon, north and west to Cape Palmas in Liberia. Null Island, defined as the intersection of the Equator and Prime Meridian (zero degrees latitude and longitude), is in the gulf.
Among the many rivers that drain into the Gulf of Guinea are the Niger and the Volta. The coastline on the gulf includes the Bight of Benin and the Bight of Bonny.
Name
The origin of the name Guinea is thought to be an area in the region, although the specifics are disputed. Bovill (1995) gives a thorough description:
The name "Guinea" was also applied to south coast of West Africa, north of the Gulf of Guinea, which became known as "Upper Guinea", and the west coast of Southern Africa, to the east, which became known as "Lower Guinea". The name "Guinea" is still attached to the names of three countries in Africa: Guinea, Guinea-Bissau, and Equatorial Guinea, as well as New Guinea in Melanesia.
From Wikipedia (CC BY-SA 4.0).