Its watershed drains nearly the entire country of Gabon, with some tributaries reaching into the Republic of the Congo, Cameroon, and Equatorial Guinea.

[8] The source of the Ogooué River was discovered in 1894 by Mary Kingsley, an English explorer who travelled up the banks by steamboat and canoe.

From the latter city, it runs west, and enters the Gulf of Guinea near Ozouri, south of Port Gentil.

Towns along the river include Ayem, Adané, Loanda, Lambaréné, Ndjole, Booué, Kankan, Maulongo, Mboungou-Mbadouma, Ndoro, Lastoursville, Moanda, and Franceville near the Congo border.

The first European explorer to trace the river to its source was Pierre Savorgnan de Brazza, who traveled in the area in the 1870s.