town and Atlantic seaport of southwestern Gabon, at the tip of a spit of land sheltering the long, narrow Mbanio Lagoon. The port handles lumber exports from the region's equatorial forest. Offshore oil has been exploited between Mayumba and Port-Gentil, 230 miles (370 km) to the northwest, since the 1960s. Net fishing is a significant industry in the Mbanio Lagoon, where abundant fish include tarpon weighing 150 pounds (70 kg) or more.

Expansive white sand beaches stretch between the ocean and the forest, which shelters elephants, buffalo, gorillas, sitatungas (antelope), crocodiles, and multicoloured birds. Rare butterflies (Anthinacus and Xalmoxys) swarm in the trees. Tourism (by bathers, fishermen, and hunters) is increasing as Mayumba becomes more accessible to other parts of Gabon. A highway connects it with Libreville, the national capital, and there is an airport. Pop. (1993) 2,845.