Elk Knob is one in a series of amphibolite mountains in the southern Appalachian range. The area contains a high diversity of natural communities, many of them uncommon or rare. A very diverse flora is found in Elk Knob State Natural Area, due partially to the high elevation and the rich soils. The rich, or "sweet" soils, are derived from the weathering of amphibolite, a metamorphic rock type. Rare and endangered plants such as Gray's lily, trailing wolfsbane, large purple fringed orchid, and flame azaleas are found in the natural area.
The North Fork of the New River has its headwaters in the high elevations of the surrounding amphibolite mountain known as Elk Knob. The New River is thought to be one of the oldest rivers in the world.
Elk Knob contains an excellent example of a northern hardwood forest which includes a beech gap subtype on the summit. The northern hardwood forest, typically found above 4000 feet in elevation, consists primarily of sugar maple, yellow birch, American beech, and yellow buckeye. Trees growing on the northern slopes and on the summit of Elk Knob are gnarled and stunted by the harsh weather conditions.
The forests and rock outcrops support breeding ravens and a number of neotropical songbirds. Black bear, bobcat, wild turkey, white tailed deer, and a number of smaller mammals inhabit this rugged mountainous area.