The Imatong Mountains (also Immatong, or rarely Matonge) are mainly located in Eastern Equatoria in southeastern South Sudan, and extend into the Northern Region of Uganda.

Since the mid-20th century the rich ecology has increasingly been severely degraded by native forest clearance and subsistence farming, causing extensive erosion of the slopes.

It is located some 190 kilometres (120 mi) southeast of Juba and south of the main road from Torit to the Kenyan border town of Lokichoggio.

These plains are crossed by many streams, separated by low, rounded ridges, and dotted with small gneiss hills, outliers of the main mountain range.

[4] The mountains are formed of crystalline basement rock that rises through the Tertiary and Quaternary unconsolidated deposits of the plains in the South Sudan-Uganda frontier zone.

The plains and the lower parts of the mountains are covered by deciduous woodland, wooded grassland and bamboo thickets to the north and west.

[11] Vegetation in the lower areas includes woodlands of Albizia and Terminalia, and mixed Khaya lowland semi-evergreen forest up to 1,000 metres (3,300 ft).

[3] The levels above 2,500 metres (8,200 ft) do not seem to have ever been inhabited by humans, but have been visited by honey-gatherers and hunters, and the fires they have started have destroyed the forest on many hill tops.

[3] According to a 1984 report, the mountains supported abundant wildlife, including healthy populations of colobus and blue monkey, bush-pig and a local sub-species of bushbuck.

The south eastern Kipia and Lomwaga Uplands were least visited by hunters and had the largest populations of elephant, buffalo, duiker, hyaena and leopard.

[3] The villages and settlements of the region are inhabited by Nilotic people including Lotuko in the east, Acholi in the west and Lango in the southern part.

Macdonald passed through the region in 1898 on a patrol towards Lado, and later the Ugandan colonial government established a post at Ikotos, just east of the mountain range.

[17] Apart from a field visit by R. Good to Gebel Marra, that obtained only a few specimens, no European botanists had investigated the mountain range's flora before 1929.

[19] In that year the botanist Thomas Ford Chipp, then deputy director of the Royal Botanic Gardens at Kew, reached the summit of Kinyeti peak.

In 1986 the government of Sudan started to provide arms, training and sanctuary for the LRA, who began to raid and plunder villages along the then Sudan–Uganda border.

After 1972 an effort was made to rehabilitate the softwood tree plantations, with a new road built from Torit, a hydro-electric scheme developed to power sawmills, and other changes.

[12] In 1984 only the Acholi mountains sub-range in the west, and the inaccessible area south east of Mount Kinyeti, were still relatively unaffected.

[25] Farming continued causing erosion, and in 1984 was evident by muddiness of the Kinyeti River in the rainy season downstream from a potato project.

[26] A proposal has been made to convert part of the Imatong Central Forest Reserve, which lies within the range, into a National Park, designating the remainder as a buffer zone.