What is the Orange River?

The Orange River is one of the longest rivers in Africa, stretching approximately 1,300 miles from the Lesotho Highlands to the Atlantic Ocean. The river rises at an altitude of about 10,800 feet (3,300 metres) above sea level on a dissected plateau formed by the Lesotho Highlands that extends from the Drakensberg escarpment in the east to the Maloti (Maluti) Mountains in the west. Along its course, it forms the eastern boundary of the South African province of Free State, as well as the boundary between Namibia and South Africa. The Orange River, along with its main tributary the Vaal River, creates a drainage basin of at least 330,000 square miles (855,000 square kilometers). The river is economically important to the region for irrigation, urbanization, and economic development.

Where is the Orange River located in Africa?

The Orange River is in southern Africa and is one of the longest rivers on the continent. Its source is in the Lesotho Highlands, less than 125 miles (200 kilometers) from the Indian Ocean. From there, it flows in a generally westerly direction for about 1,300 miles (2,100 kilometers) to the Atlantic Ocean. The river crosses the veld region of South Africa, defines the southern limit of the Kalahari, and bisects the southern Namib before draining into the Atlantic at Alexander Bay, South Africa. Along its course, it forms the eastern boundary of the South African province of Free State, as well as the boundary between Namibia and South Africa.

Which countries does the Orange River flow through?

The Orange River flows through three countries in southern Africa: * Lesotho : The Orange River rises in the Lesotho Highlands. * South Africa : The river traverses the veld region of South Africa. * Namibia : The Orange River defines the boundary between Namibia and South Africa and bisects the southern Namib The Orange River flows in a generally westerly direction for approximately 1,300 miles before draining into the Atlantic Ocean at Alexander Bay, South Africa. The river is of vital economic importance to the region through which it flows.

Why is the Orange River important for the people living near it?

The Orange River is of significant economic importance to the region it traverses. The Orange River Project and the Lesotho Highland Project were designed to meet the water demand for irrigation, urbanization, and economic development in the central industrial areas of South Africa. The high valleys of the Orange River are mostly uninhabited, but the plateaus are grazing land for the southern Sotho people. Irrigated sections occur along the river where cotton, alfalfa, grapes, and dates are grown. Much of the water accumulated by dams is diverted to other river valleys and cities. Navigation is impossible on the river due to its irregular flow and the presence of falls and rapids.

What plants and animals can be found along the Orange River?

The Orange River flows through diverse terrains, supporting varied flora and fauna. Natural vegetation ranges from savanna to scrub and desert vegetation. Along the river, especially in irrigated areas between Upington and Augrabies Falls, you’ll find cultivated plants such as cotton, alfalfa, grapes, and dates. Regarding animals, the area supports a variety of species. South Africa is home to more than 200 species of mammals, including lions, leopards, elephants, rhinoceroses, hippopotamuses, baboons, and zebras. Additionally, over 800 bird species, numerous reptiles, and a diverse insect population can be found in the region.

How have people used the Orange River for farming and energy production?

The Orange River is vital for the economy, providing water for irrigation, urbanization, and industry. Farmers use irrigated sections along the river to grow cotton, alfalfa, grapes, and dates. To manage the river's resources, the Orange River Project was initiated, featuring dams and canals. The Gariep and Van der Kloof Dams not only help control heavy silt accumulation but also have hydroelectric power stations. These projects help meet the water demands for irrigation and provide water-recreation facilities.

Orange River

References & Edit History Related Topics

Images

Physical map of southern Africa showing elevation with color shading, major rivers including the Orange River, national boundaries, cities, mountain ranges, deserts such as the Kalahari, and features like salt flats, swamps, and waterfalls. Surrounding countries include Namibia, Botswana, Zimbabwe, Mozambique, Zambia, Angola, South Africa, Lesotho, and Eswatini. An inset locator map highlights the region within the African continent.

The Gorge Tract of the Orange River, near Rosh Pinah, Namibia.

At a Glance

Orange River summary

Orange River

river, Africa

Also known as: Gariep River

Written by

Johann CooksAll

Fact-checked by

Britannica Editors

Last updated

Oct. 23, 2026 •History

Top Questions

What is the Orange River?
The Orange River is one of the longest rivers in Africa, stretching approximately 1,300 miles from the Lesotho Highlands to the Atlantic Ocean. The river rises at an altitude of about 10,800 feet (3,300 metres) above sea level on a dissected plateau formed by the Lesotho Highlands that extends from the Drakensberg escarpment in the east to the Maloti (Maluti) Mountains in the west. Along its course, it forms the eastern boundary of the South African province of Free State, as well as the boundary between Namibia and South Africa.

The Orange River, along with its main tributary the Vaal River, creates a drainage basin of at least 330,000 square miles (855,000 square kilometers). The river is economically important to the region for irrigation, urbanization, and economic development.
1 Britannica Source
1. Orange River
Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.
Where is the Orange River located in Africa?
The Orange River is in southern Africa and is one of the longest rivers on the continent. Its source is in the Lesotho Highlands, less than 125 miles (200 kilometers) from the Indian Ocean. From there, it flows in a generally westerly direction for about 1,300 miles (2,100 kilometers) to the Atlantic Ocean. The river crosses the veld region of South Africa, defines the southern limit of the Kalahari, and bisects the southern Namib before draining into the Atlantic at Alexander Bay, South Africa. Along its course, it forms the eastern boundary of the South African province of Free State, as well as the boundary between Namibia and South Africa.
1 Britannica Source
1. Orange River
Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.
Which countries does the Orange River flow through?
The Orange River flows through three countries in southern Africa:
* Lesotho: The Orange River rises in the Lesotho Highlands.
* South Africa: The river traverses the veld region of South Africa.
* Namibia: The Orange River defines the boundary between Namibia and South Africa and bisects the southern Namib
The Orange River flows in a generally westerly direction for approximately 1,300 miles before draining into the Atlantic Ocean at Alexander Bay, South Africa. The river is of vital economic importance to the region through which it flows.
2 Britannica Sources
1. South Africa: Drainage
2. Orange River
Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.
Why is the Orange River important for the people living near it?
The Orange River is of significant economic importance to the region it traverses. The Orange River Project and the Lesotho Highland Project were designed to meet the water demand for irrigation, urbanization, and economic development in the central industrial areas of South Africa.

The high valleys of the Orange River are mostly uninhabited, but the plateaus are grazing land for the southern Sotho people. Irrigated sections occur along the river where cotton, alfalfa, grapes, and dates are grown. Much of the water accumulated by dams is diverted to other river valleys and cities. Navigation is impossible on the river due to its irregular flow and the presence of falls and rapids.
1 Britannica Source
1. Orange River
Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.
What plants and animals can be found along the Orange River?
The Orange River flows through diverse terrains, supporting varied flora and fauna. Natural vegetation ranges from savanna to scrub and desert vegetation. Along the river, especially in irrigated areas between Upington and Augrabies Falls, you’ll find cultivated plants such as cotton, alfalfa, grapes, and dates.

Regarding animals, the area supports a variety of species. South Africa is home to more than 200 species of mammals, including lions, leopards, elephants, rhinoceroses, hippopotamuses, baboons, and zebras. Additionally, over 800 bird species, numerous reptiles, and a diverse insect population can be found in the region.
2 Britannica Sources
1. South Africa: Flora and fauna
2. Orange River
Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.
How have people used the Orange River for farming and energy production?
The Orange River is vital for the economy, providing water for irrigation, urbanization, and industry. Farmers use irrigated sections along the river to grow cotton, alfalfa, grapes, and dates.

To manage the river's resources, the Orange River Project was initiated, featuring dams and canals. The Gariep and Van der Kloof Dams not only help control heavy silt accumulation but also have hydroelectric power stations. These projects help meet the water demands for irrigation and provide water-recreation facilities.
1 Britannica Source
1. Orange River
Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

Orange River, river in southern Africa, one of the longest rivers on the continent and one of the longest south of the Tropic of Capricorn. After rising in the Lesotho Highlands, less than 125 miles (200 kilometres) from the Indian Ocean, the river flows to the Atlantic Ocean in a generally westerly direction for some 1,300 miles. The Orange traverses the veld region of South Africa, after which it defines the southern limit of the Kalahari and bisects the southern Namib before draining into the Atlantic at Alexander Bay, S.Af. Along its course the river forms the eastern boundary of the South African province of Free State, as well as the boundary between Namibia and South Africa.

The Orange River—together with the Vaal, its principal tributary—forms a drainage basin with an area of at least 330,000 square miles (855,000 square kilometres). The western part of the basin is generally dry, flat, and unamenable to cultivation without irrigation. The river itself is of vital economic importance to the region through which it flows. Two projects—the Orange River Project and the Lesotho Highland Project, both in various stages of construction—have been designed to meet the water demand for irrigation, urbanization, and economic development in the central industrial areas of South Africa.

Physical features

Physiography

The headwaters of the Orange River rise at an altitude of about 10,800 feet (3,300 metres) above sea level on a dissected plateau formed by the Lesotho Highlands that extends from the Drakensberg escarpment in the east to the Maloti (Maluti) Mountains in the west. The main source of the Orange River is officially recognized as the Sinqu (Senqu) River, which rises near the plateau’s eastern edge. The Seati (Khubedu) headwater rises near Mont-aux-Sources to the north. Still farther north is the lesser-known Malibamatso headwater, one site of the Lesotho Highland Project. The Lesotho headwaters flow over the turf soil that covers Drakensberg lava and cut through the lava to expose underlying sedimentary rocks; material eroded from these rocks contributes to heavy silt deposits farther down the river’s course.

By clicking “Sign Up”, you consent to the Britannica Privacy Policy and Terms of Use.

After entering South Africa southwest of Lesotho, the river flows south and west through more open country, where sandstones, shales, and mudstones appear on the surface and where hard dolerite outcrops form small hills and flat-topped mountains. Near Maletswai (formerly Aliwal North) the river has eroded a broad valley some 30 miles wide and more than 1,000 feet deep. The river’s channel, however, varies greatly in both width and depth because of dolerite outcrops that sometimes narrow it to 3,000 or 4,000 feet. The river receives the Caledon as a tributary at the head of the Gariep (formerly Hendrik Verwoerd) Reservoir.

From the Gariep (formerly Hendrik Verwoerd) Dam the Orange swings to the northwest to its confluence with the Vaal River. The Vaal, which rises in Eastern Transvaal province, flows west through the major population and industrial core of South Africa before turning south and joining the Orange near the town of Douglas. The Orange then turns southwest and flows over calcrete and tillite (glacial clayey deposit). At Prieska it makes another sharp bend to the northwest, and this marks the beginning of its middle course. Quartzites and ironstones form a “barrier zone” through which the river has cut deep gorges. At Upington the river—by then flowing westward—spreads out over a granite surface. In this area the Orange splits up into innumerable channels, between which are islands of varying length; and the river attains its greatest width, which may reach nearly four miles in places. About 40 miles downstream from Upington, however, the riverbed is suddenly narrowed to about 2,000 feet.

Tower Bridge over the Thames River in London, England. Opened in 1894. Remains an Important Traffic Route with 40,000 Crossings Every Day.

Britannica Quiz

Guess the City by Its River Quiz

Some 20 miles below Kakamas the Orange—again flowing in several channels—forms the Augrabies Falls. There, after descending in a series of rapids, the river plunges into a deep pool. The river flows through an almost vertical-sided gorge for about 11 miles, emerging again into more open country. The lower course of the river, from the Augrabies Falls to the sea, is sometimes called the Gorge Tract. Where the rock surface is soft, the river valley is generally open. Where the river traverses harder igneous rock, however, it is confined between almost vertical cliffs more than 1,000 feet high in places. Some of the Orange’s most rugged passages are found in the last section of the river, as it flows along the Richtersveld before turning west to the Namib coastal desert.

The Orange reaches the sea a few miles north of the little inlet known as Alexander Bay. The mouth is less than three miles wide and is nearly closed by sandbars, which are widely breached during high floods. The gap in the southern end of the bars is maintained by the outflow of water from the river mouth during low tides and by the tidal inflow at high tides.

Explore Britannica Premium!

The trusted destination for professionals, college students, and lifelong learners.

Climate and hydrology

The rainfall patterns in the Orange basin have a direct effect on the river’s rate of flow. In Lesotho, above the confluence with the Caledon, the rainfall averages 28 to 32 inches (700 to 800 millimetres) annually; and, combined with the melted winter snows of the highland areas, this small area contributes nearly 60 percent of the Orange River’s total annual flow. From the Caledon to the Vaal annual rainfall decreases to about 11 to 16 inches a year, and below the Vaal confluence it decreases from 9 inches to less than 2 inches in the Namib.

The amount of rainfall reaching the river as runoff decreases from about 16 percent in Lesotho to less than one-half of 1 percent in the lower Orange catchment. Conversely, summer maximum temperatures increase from east to west, the high exceeding 86° F (30° C) on an average 5 days per year in Lesotho and 150 days per year in the west. The result of these phenomena is a tremendous increase in the rate of evaporation from east to west. Waters lost to evaporation may amount to 12 times the total precipitation in the lower course of the Orange, and the potential storage capacity of reservoirs in the drier regions may be reduced by up to 60 percent.

Orange River

Physical features

Physiography

Thank you for signing up!

Climate and hydrology