Sudan is located in Northeast Africa. It is bordered by Egypt to the north, the Red Sea to the northeast, Eritrea and Ethiopia to the east, South Sudan to the south, the Central African Republic to the southwest, Chad to the west and Libya to the northwest. Covering , it is the third largest country in Africa, after Algeria and the Democratic Republic of the Congo. It was the largest country on the continent until South Sudan split off from it in 2011.
Geographical regions
[[File:Political Regions of Sudan, July 2010.svg|thumb|right|
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Northern Sudan – lying between the Egyptian border and Sennar – has two distinct parts, the desert and the Nile Valley. To the east of the Nile is the Nubian Desert and to the west, the Libyan Desert.
As a result of the Comprehensive Peace Agreement signed in 2005, the Abyei Area was given special administrative status and following the independence of South Sudan in 2011, is considered to be simultaneously part of both the Republic of Sudan and the Republic of South Sudan, effectively a condominium.
Area and boundaries
;Area:
:* Total:
:**country rank in the world: 15th
:* Land: and other rivers, in lakes and reservoirs and in the Red Sea.
River Islands
Tuti Island, Aba Island, Badien Island, Sai Island.
Red Sea Islands
Dungunab Bay
Mukawwar Island (Jazirat Magarsam), Jazirat Mayteb, Jazirat Bayer, Juzur Telat.
Suakin Archipelago
Talla Talla, Kebir Island, Taimashiya Island, Dar Ah Teras, Andi Seli, Masamarhu Island, Abu Isa Island, Dahrat ed Dak Hillat Island, Ed Dom esh Sheikh Island, Darrakah, Miyum, Zahrat Ghab, Jazirat Zahrat Abid, Gazirat Iri, Sayl Bahr, Gazirat Abid, Gazirat Wahman, Jaza'ir Amarat, Quban Island, Bakiyai Islands, Gazair Hayyis Wa Karai, Saqir Island, Sumar Island, Long Island, Gap Island, Two Islands.
Lake and Reservoir Islands
Roseires Reservoir
Jazirat Maqanza, Jazirat Abu Ushar, Jazirat Muluwwa.
Jebel Aulia Reservoir
Gazerat Jene't.
Er Rahad Lake
Four small islands and several islets.
Climate
thumb|A [[Köppen climate classification map of Sudan.]]
thumb|Sudan is the thirteenth most water stressed country in the world.
Although Sudan lies within the tropics, the climate ranges from hyper-arid in the north to tropical wet-and-dry in the far southwest. Temperatures do not vary greatly with the season at any location; the most significant climatic variables are rainfall and the length of the wet and dry seasons. NOAA (extremes and humidity 1961–1990)
|source 2 = Deutscher Wetterdienst (sun, 1961–1990)
|date=August 2010
Hydrology
thumb|Nile and its tributaries in Sudan
Except for a small area in northeastern Sudan, where wadis discharge the sporadic runoff into the Red Sea and rivers from Eritrea that flow into shallow evaporating ponds west of the Red Sea Hills, the entire country is drained by the Nile and its two main tributaries, the Blue Nile and the White Nile. The longest river in the world, the Nile flows for 6,737 kilometers from its farthest headwaters in Central Africa to the Mediterranean. The Blue Nile’s two main tributaries, the Dindar and the Rahad, have headwaters in the Ethiopian highlands and discharge water into the Blue Nile only during the summer high-water season. Less extensive and widely separated, but of major economic importance, is another group consisting of alluvial soils found along the lower reaches of the White Nile and Blue Nile, along the Nile to Lake Nubia, in the delta of the Qash River in the Kassala area, and in the Baraka Delta in the area of Tawkar near the Red Sea in Kassala State.