Benin, Bight of, northern arm of the Gulf of Guinea, c.550 mi (885 km) wide, W Africa, between Cape Three Points, S Ghana, and the Niger River delta, SW Nigeria. The bight was an important area for slave trading between the 16th and 19th cent. After the 19th cent. palm oil trading became fo primary importance. In the late 1950s oil was discovered in the Niger River delta.