Cyamudongo Forest is a small relict forest located in the far south-west of the country, close to the town of Nyakabuye near the border with the DR Congo. Historically, it was connected to Nyungwe Forest to the east, but its vegetation is denser, with fewer clearings. Common tree species include Chrysophyllum gorungosanumCroton spp., Newtonia buchananiiAlangium chinense and Leptonychia melanocarpa.

Although impoverished due to its small size, compared with nearby Nyungwe, Cyamudongo Forest holds many species typical of the Albertine Rift forests, including Kungwe apalis (Apalis argentea). Ross’s turaco (Musophaga rossae), which is not found in Nyungwe, is common in Cyamudongo, while the only Rwandan record of Red-thighed sparrowhawk (Accipiter erythropus) is from here. In addition, four species of the Guinea–Congo Forests biome have also been recorded.

The primate especially Chimpanzees are what the forest is known for and its high diversity of butterfly species.