(Period of data: 1940–1999)4,750 m/s (168,000 cu ft/s)

(Period: 1971–2000)4,485.4 m/s (158,400 cu ft/s) • minimum1,610 m/s (57,000 cu ft/s) • maximum9,440 m/s (333,000 cu ft/s) Discharge  • locationNdjolé, Gabon (Basin size: 158,100 km (61,000 sq mi)) • average(Period: 1971–2000)3,194.8 m/s (112,820 cu ft/s) • minimum1,200 m/s (42,000 cu ft/s) • maximum6,600 m/s (230,000 cu ft/s) Discharge  • locationLastoursville, Gabon (Basin size: 47,700 km (18,400 sq mi)) • average1,304.6 m/s (46,070 cu ft/s) • minimum650 m/s (23,000 cu ft/s) • maximum2,800 m/s (99,000 cu ft/s) Discharge  • locationFranceville, Gabon (Basin size: 8,670 km (3,350 sq mi)) • average(Period of data: 1953–1981)253 m/s (8,900 cu ft/s) • minimum122 m/s (4,300 cu ft/s) • maximum520 m/s (18,000 cu ft/s) Basin featuresRiver systemOgooué RiverTributaries  • leftLetili, Lebombi, Lekedi, Leyou, Lolo, Offoue, Ngounié • rightMpassa, Léconi, Sebe, Lassio, Dilo, Ivindo, Nké, Okano, Abanga

The Ogooué (or Ogowe), also known as the Nazareth River, some 1,200 km (750 mi) long, is the principal river of Gabon in west-central Africa and the fourth largest river in Africa by volume of discharge, trailing only the Congo, Kasai and Niger. Its watershed drains nearly the entire country of Gabon, with some tributaries reaching into the Republic of the Congo, Cameroon, and Equatorial Guinea.

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. The river rises in the northwest of the Bateke Plateaux near Kengue, Republic of Congo. It runs northwest, and enters Gabon near Boumango. Poubara Falls are near Maulongo. From Lastoursville up to Ndjole, the Ogooué is non-navigable due to rapids. From the latter city, it runs west, and enters the Gulf of Guinea near Ozouri, south of Port Gentil. The Ogowe Delta is quite large, about 100 km long and 100 km wide.

A 30,000 ha site in the delta of the Ogooué River, including much of Mandji Island, has been designated an Important Bird Area (IBA) by BirdLife International because it supports significant populations of many bird species.

The Ogooué Basin is 223,856 km (86,431 sq mi), of which 173,000 km (67,000 sq mi) or 73 percent lies within Gabon. It mostly consists of undisturbed rainforest with some savanna grassland where the mid-year dry season is longest. It is home to a high biodiversity. All three species of African crocodile, for instance, occur in the river: the Nile crocodile, the dwarf crocodile, and the slender-snouted crocodile. It is also the type locality for the catfish Synodontis acanthoperca.

The Mpassa River is a tributary of the Ogooué River. The Ndjoumou River is the main tributary of Mpassa River.

Distance from river mouth

Station	(km)	Altitude (m)
Lambaréné	183	12
Ngounié*	196	13
Abanga*	242	20
Ndjolé	280	25
Okano*	314	40
N'golo*	359	72
Offoué*	424	142
Booué	451	161
Ivindo *	481	180
Dilo*	503	182
Lolo*	512	186
Lassio*	535	200
Lastoursville	616	226
Sébé*	685	242
Leyou*	696	243
Léconi*	714	248
Lékabi*	725	249
Lébombi*	774	270
Mpassa*	802	280
Baniaka*	871	426

*River in confluence

The Ogooué is navigable from Ndjole to the sea. It is used to bring wood to the Port Gentil Harbour.

The Ogowe Basin includes several major conservation reserves, including Lope National Park.

The catchment area has an average population density of 4 people per km². Towns along the river include Ayem, Adané, Loanda, Lambaréné, Ndjole, Booué, Kankan, Maulongo, Mboungou-Mbadouma, Ndoro, Lastoursville, Moanda, and Franceville near the Congo border.

Towns in Congo include Zanaga.

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

The Ogowe River receives water of numerous tributaries including:

• Abanga, which rises in the Cristal Mountains, near Medouneu
• Baniaka
• Dilo
• Iyinda, the most important tributary
• Letili
• Lassio
• Lebombi
• Lekabi
• Lekedi
• Lekoni, which flows across Akieni and Leconi
• Letili
• Leyou
• Lolo
• Mbine
• Ngolo
• Ngounie
• Nke
• Offoue
• Okano, whose main tributary is the Lara River
• Mpassa, which flows across Franceville
• Sebe, which flows past Okondja
• Wagny

The main river and tributaries are (sorted in order from the mouth heading upstream):

Left tributary	Right tributary	Length (km)	Basin size (km²)	Average discharge (m/s)
Nkomi		170	8,900	275
Ngounié		680	33,100	1,002.4
	Biné			21
M'boumi				35.1
	Abanga	226	7,800	190.3
	Okano	280	10,900	192.9
	Ngolo			14.6
Mingoué				21.2
Leledi				33.2
Offoué		235	7,300	129.3
	Nké		1,600	26
	Ivindo	570	62,700	1,057.8
	Dilo	160		54.3
Lolo		240	9,700	219.4
	Lassio	160	4,000	114.4
	Sébé	232	11,900	237
Leyou			1,900	45.5
	Lékoni	160	7,600	242.2
	Lékabi		2,100	46.7
Lekedi			800	34.6
Lébombi			3,400	106.9
	Mpassa	136	6,400	226.3
Baniaka				21.4
Letili				43.5
	Loua			11
Djoulou				12.7
Loungou				11.4
Léfou				8.9
Léouké				23.3
	Nsiele			14.1

• Perusset André. 1983. Oro-Hydrographie (Le Relief) in Geographie et Cartographie du Gabon, Atlas Illustré led by The Ministère de l'Education Nationale de la Republique Gabonaise. Pg 10-13. Paris, France: Edicef.
• Petringa, Maria. Brazza, A Life for Africa. Bloomington, IN: AuthorHouse, 2006. ISBN 9781-4259-11980. Describes Pierre Savorgnan de Brazza's extensive explorations of the Ogoué River basin.
• National Geographic. 2003. African Adventure Atlas Pg 24,72. led by Sean Fraser.
• Gardinier David. 1994. Historical Dictionary of Gabon 2nd Edition. USA: The Scarercrow Press, Inc.
• Direction General de L'Environnement.1999. Stratégie nationale et Plan D'action sur la biodiversité biologique du Gabon.
• The Atlas of Africa. Pg 201. by Regine Van Chi-Bonnardel. Jeune Afrique Editions.
• Lerique Jacques. 1983. Hydrographie-Hydrologie. in Geographie et Cartographie du Gabon, Atlas Illustré led by The Ministère de l'Education Nationale de la Republique Gabonaise. Pg 14-15. Paris, France: Edicef.

• World Resources Institute map of Ogooué watershed
• Map of the Ogoué River basin at Water Resources eAtlas
• Maria Petringa's 1997 "Pierre Savorgnan de Brazza: Brief Life of a Lover of Africa" about Brazza's extensive explorations of the Ogoué River basin
• Website about the dinosaur hunt

2°40′S 14°30′E / 2.667°S 14.500°E / -2.667; 14.500