Utamboni kogi ne na yankin kudu maso yammacin babban yankin Equatorial Guinea. Ya gudana tare da kan iyaka da Gabon kuma ya zama wani ɓangare na Muni Estuary tare da Kogin Mitimele (babban ɓangaren kogin), Kogin Mitong, Kogin Mandyani, Kogin Congue, da Kogin Mven. Kogin ya zama Kogin Utamboni tare da iyaka da Gabon. Sundiata, I. K. (1990). Equatorial Guinea: colonialism, state terror, and the search for stability. Westview Press. p. 6. ISBN 978-0-8133-0429-8. Retrieved 30 March 2012. Hughes, R. H.; Hughes, J. S. (1992). A Directory of African Wetlands. IUCN. p. 501. ISBN 978-2-88032-949-5. Retrieved 30 March 2012.