Occoneechee Mountain State Natural Area showcases a diversity of natural communities, and such diversity is found nowhere else in the Triangle area. The relatively undisturbed forest of the ridge top includes one of the best chestnut oak stands in the region. And, the mountain area itself, adjacent to the upper Eno River, is important wildlife habitat. The acorns and berries produced by the chestnut oaks and other area plants support a population of animals, including deer, groundhog and wild turkey.
The top of Occoneechee Mountain's ridge and northern slopes provide habitat for a wide variety of wildlife species that are typically found in the mountains, and some plant species reach their easternmost limits here. These include Bradley's spleenwort and wild sarsaparilla. Catawba rhododendron is present on the steep rock outcrop adjacent to the ravine, and a mountain laurel-galax community grows on the ravine's slopes. Sweet pinesap, another rare plant, also grows here, along with large witch-alder. Yet another mountainous species that grows in the natural area is the purple fringeless orchid.
In addition, several rare animal species found nowhere else in the region are present in the park. These include the brown elfin butterfly. Separated by more than 100 miles from other brown elfin populations in the mountains, the brown elfin butterfly is believed to have survived at Occoneechee Mountain since the Ice Age. Although the brown elfin is found virtually nowhere else in the Piedmont, the population on Occoneechee Mountain is quite large.