Spruce Knob is the highest point in the eastern United States between the Adirondacks of New York and Mount Rogers (part of the Blue Ridge Mountains) in southern Virginia.

The summit is accessible both via trails and a paved Forest Service road, and is crowned with a stone lookout tower amid a mixture of boulder fields, meadows and trees.

Dropping steeply to the east, it offers views of the Germany Valley and North Fork Mountain; to the west is the Allegheny Plateau.

Mid-ocean subduction created a volcanic arc (now known as the Blue Ridge Mountains) which eventually collided with the North American Plate.

[2] The accumulation of shells and other hard parts of marine organisms (made of CaCO3, calcium carbonate) at the bottom of the shallow inland sea cemented into a layer of Greenbrier Limestone.

This caused fine grains of mud and silt to settle out and lithify into a layer of Mauch Chunk Shale on top of the Greenbrier Limestone.

As the Blue Ridge eroded, rivers carried sediment down to the low-lying areas that formed a layer of Pottsville Conglomerate on top of the shale.

The large boulders on the summit are remnants of this layer, and outcrops of both Mauch Chunk Shale and Greenbrier Limestone can be found lower on the mountain.

[3] When the North American and African Plates finally collided around 250 mya, it caused a massive uplift that folded and faulted these layers of sedimentary rock.

Winters are cold and snowy, with an average of around 180 inches (4.6 m) of annual snowfall leaving the summit access road often impassible between October and April.

Blizzard conditions can develop in minutes behind cold frontal passages and last days with upslope snowfall continuing with northwest winds, making travel on the mountain dangerous during the colder months.

[6] ) The present second-growth forest of Spruce Mountain is characterized by a dominance of sugar maple (Acer saccharum), American beech (Fagus grandifolia), and yellow birch (Betula lutea).

Other characteristic species of the mixed mesophytic forest region are also present: tuliptree (Liriodendron tulipifera), basswood (Tilia heterophylla, T.floridana, T. neglecta), chestnut (Castanea dentata), yellow buckeye (Aesculus flava), red oak (Quercus borealis), white oak (Q. alba), and eastern hemlock (Tsuga canadensis).