It consisted of Río Muni, the continental region of modern-day Equatorial Guinea, plus the islands of Corisco and Elobey.

In 1959, it became the Province of Río Muni within the autonomous region of Equatorial Guinea, a name it kept until its independence from Spain in 1968.

[2] On 1 September 1960 the Provincial Deputation of Río Muni [es] was established in the city of Bata, whose first president was José Vedú.

[4] Previously the prefix was "TEG" (Territorios Españoles del Golfo de Guinea), established by the order of 30 September 1929, territories that were divided into two provinces by the Law of 29 July 1959.

Other towns of importance were Evinayong, Ebibeyin, Cogo, Acurenam, Mongomo, Micomeseng, Niefang, Añisoc and Rio Benito.