This vast site is located 48 km north-east of Ambatondrazaka, in the forest corridor between Mantadia and Zahamena National Parks (IBAs MG054 and MG047). Within the site are four Classified Forests: Iofa, Didy, Andriantantely and Sandranantitra. Andriantantely is covered in low-altitude, dense, humid evergreen forest, while the other three are mid-altitude, dense, humid evergreen forest.The terrain is undulating, with mid-altitude mountainous massifs. The main rivers flowing through the site are the Namolazana, Ivondro, Vokovoko, Taheza and Rianila.
See Box and Tables 2 and 3 for key species. Eighty-two species are known from the site, of which 53 are endemic to Madagascar. This site, especially the forest around Didy and Rogez, was much frequented by the first ornithological explorers of Madagascar, in the 1800s. Recent inventories show that it still holds most of the species previously recorded.