SNR "Gornje Podunavlje" is one of finest pearls placed along the course of Danube in Vojvodina and Serbia. This reserve comprises remains of former vast inundated Danube areas. It consists of several separate sites: Monoštorski rit (Monoštor marshes), Apatinski rit (Apatin marshes), Štrpce area, Kozara and Karapandža. The reserve represents a complex mosaic of water and land ecosystems. The greater part of the reserve is covered by marshy, inundated forest complexes. This type of preserved indigenous biotopes is very rare both in our country and Europe. It makes up a natural whole with the right bank, an inundated area in Baranja in Croatia, well-known for its Kopački rit (Kopački marshes) and inundated area Karapandža in Hungary.

It is located on an alluvial plateau and terrace of Danube between 80 and 88 metres above sea level. It has a distinct microrelief. Geological composition consists of Quaternary formations which constitute a caprock over Pliocene sediments. The soil comprises alluvial riparian deposits, mainly recent, fresh alluvium. New deposits settle on parts this alluvium after floods. There is also marshy soil lined with a layer of gley, whereas higher parts contain marshy black soil and chernozem with patches of saline soil. The course of Danube, together with its backwaters called ‘Dunavci' and inundated areas, left its imprint on the area of Gornje Podunavlje. Its slow and winding course creates backwaters, meanders, and stills. Its floods created marshes, ponds and swamps. SNR ‘Gornje Podunavlje' is an important center of biodiversity. The wealth of this biodiversity is reflected in a great number of vegetation types comprising 156 different syntaxonomic units in 14 classes, 18 orders, 32 alliances and 51 plant communities with over 1,000 species of plants.  This wealth is also shown by the presence of 55 species of fish, 11 species of amphibians, 9 species of reptiles, 230 species of bids and  51 species of mammals as well as numerous invertebrates, especially butterflies with over 60 species of daytime butterflies.

Owing to its exceptional natural values Gornje Podunavlje was designated as an Important Bird Area in 1989 (IBA); it is also an integral part of potential Biosphere Reserve Drava-Mura and one of Ramsar Site candidate wetlands.