Il-Qortin tal-Magun, the eastern part of which is also known as il-Qortin il-Kbira, is located within Nadur local council, separated from the more northerly Qortin Isopo by Wied ir-Raħħan. The mosaic of geomorphological features is a result of the geological formations that are exposed in the Nadur area, namely the upper coralline limestone and the blue clay formations, and the coastal location of the site, thus being exposed to coastal processes. The upper coralline limestone caps the plateaus of the two promontories, creating a rugged surface topography that is exploited by garigue vegetation. The blue clay formation (which underlies the upper coralline limestone) is exposed all along the coast where it forms clay slopes gently sloping towards the sea.

The plateau of il-Qortin tal-Magun supports one of the most important garigue communities in the Maltese Islands, which apart from harbouring a number of very rare species, also constitute a unique assemblage of species present within a highly dense vegetation community. The plateau represents the most pristine and dense expanse of such garigue communities within the area.

Il-Qortin tal-Magun (and the biogeographically correlated Qortin Isopo) constitute one of only two sites where the white rock rose (Cistus monspeliensis) occurs in the Maltese islands, the other locality being Wied Rini in mainland Malta. Albeit being rare throughout the Maltese islands, a particularly dense population of this species is found on both promontories. The rock rose constitutes a dominant species together with the tree spurge (Euphorbia dendroides), the Mediterranean thyme (Thymus capitatus) and the shrubby kidney-vetch (Anthyllis hermanniae).

Mepa scheduled the geomorphological features and the associated floral assemblages of Il-Qortin Isopo, Il-Qortin tal-Magun as a Level 1 Area of Ecological Importance and a Level 1 Site of Scientific Importance as per Government Notice No. 712/06 in the Government Gazette dated August 11, 2006.