The large Sudd swamps of the Upper Nile and its inhabitants, the Dinka

The Sudd (as-Sud

d or al-Sudd) is a vast swampy area in South Sudan, formed by the White NIle's Bahr al-Jabal section. The Arabic word sudd is derived from sadd meaning "barrier" or "obstruction"

 The term "the sudd" has come to refer to any large solid floating vegetation island or mat. The area which the swamp covers is one of the world's largest wetlands and the largest freshwater wetland in the Nile basin.

For many years the swamp, and especially its thicket of vegetation, proved an impenetrable barrier to navigation along the Nile. In AD 61, a party of Roman soldiers sent by the Emperor Nero roceeded up the White Nile but were not able to get beyond the Sudd, which marked the limit of Roman penetration into equatorial Africa.^[

 For the same reasons in later times the search for the source of the NIle was particularly difficult; it eventually involved overland expeditions from the central African coast, so as to avoid having to travel through the Sudd.

Vegetation cover of the area can generally be classified in five categories which depend on the elevation of the area above river flood level: the lakes and rivers themselves, the floating plant life of the swamp, river-flooded grasslands (Toic), rain-flooded grasslands, and wooded grasslands on the fringes. Grassland and woodland areas have been cultivated by local populations.

Dinka, Nuer and Shiluk pastoralists use the Sudd and the surrounding areas extensively. Livestock and rain-fed agriculture are the dominant means of support for the largely rural population for which the seasonal flooded grasslands along the Sudd provides valuable grazing lands.

Vegetation cover of the area can generally be classified in five categories which depend on the elevation of the area above river flood level: the lakes and rivers themselves, the floating plant life of the swamp, river-flooded grasslands (Toic), rain-flooded grasslands, and wooded grasslands on the fringes. Grassland and woodland areas have been cultivated by local populations.

The main nation living in the Sudd are the Dinka.

They are pastoralists use the Sudd and the surrounding areas extensively. Livestock and rain-fed agriculture are the dominant means of support for the largely rural population for which the seasonal flooded grasslands along the Sudd provides valuable grazing lands.^[7

 The Dinka mainly live on traditional agriculture and pastoralism, relying on cattle husbandry as a cultural pride, not for commercial profit or for meat, but cultural demonstrations, rituals, marriages' dowries and milk feedings for all ages. The Dinka cultivate food crops and cash crops. The food crops are grains, mainly sorghum and millet. The cash crops include groundnuts, sesame and gum-arabic. Cattle are confined to riversides, the Sudd and grass areas during the dry season, but are taken to high grounds in order to avoid floods and water during the rainy season.