Virginia is not flat. Elevation varies from sea level in Tidewater rivers east of the Fall Line to the tallest peak, Mount Rogers in Grayson County, at 5,729 feet.
For many years, Thomas Jefferson and other Virginians thought the the highest spot in the colony/state of Virginia was the Peaks of Otter, in part because Flat Top and Sharp Top stood out as distinct peaks compared to the adjacent ridges. Jefferson recognized that the mountains in Virginia were low ridges, compared to the tall peaks in South America and Europe:1
Jefferson hoped that the low height of the Appalachians meant that mountains in the western states would be equally low. After being elected president in 1800, he sent Meriwether Lewis and William Clark on an expedition to find a pathway from the Missouri River to the Pacific Ocean. If the French concept of "symmetrical geography" was correct, then the western edge of the North American continent would be a mirror image of the eastern edge. If Lewis and Clark discovered low mountains commencing about 150 miles from the western seacoast, disposed in ridges one behind another, then American trade routes from the newly-acquired Louisiana Territory to the Pacific Ocean would be easy to develop.2 (Lewis and Clark discovered the Rocky Mountains, once again proving that field checking a theory such as symmetrical geography is essential...)
Peaks of Otter (Bedford County)
Source: National Park Service
What is tall enough to be called a "mountain" in Virginia? There are no official criteria for distinguishing a "mountain" vs. a "hill." Local custom determines place names. The US Board of Geographic Names has no formal standards that require government officials to override common names created by local residents. (Paul Larson at Southern Utah University has suggested "the difference between a mountain and a hill is in vegetation changes. If it is high enough for vertical zonation to occur it is a mountain, but if the same vegetation type covers the entire height of the feature, it is a hill."3)
Today, we know that Grayson County is the "roof" of Virginia, the county with the highest average elevation and the highest peaks in Virginia.4 To a casual visitor, Whitetop Mountain appears to be taller than Mount Rogers. Whitetop, like the Peaks of Otter, stands slightly apart from other places. The treeless, bald appearance (the white top...) also makes the mountain more eye-catching than nearby Mount Rogers. However, if the Fraser firs and red spruces covering Mount Rogers and blocking the view from the top continue to die off, then there's a chance that the highest point in Virginia will be easier to recognize.
Using the 1:24,000 scale topographic maps produced by the US Geological Survey, we can identify the individual summits in Virginia. A topo quadrangle map that has not been updated for 50 years will still have accurate elevation data, even though the indications of land use (especially boundaries of urban/suburban development) may be inaccurate.
According to the Geographic Names Information System (GNIS), Virginia has about 1,850 features named a "summit" (about 100 over 4,000 feet tall), plus almost 700 records of a "ridge." However, height is a relative feature. In Accomack County, the named ridges are low in elevation, but the slight difference in height above the surrounding land is important enough to be affect the drainage and to be noticed. Bulls Head in Accomack County is called a summit - even though the site is just 2 feet above sea level.
At 5,729 feet, Mount Rogers is taller than the mile-high city of Denver. However, the mountains in Virginia are not breath-taking peaks, because there is rarely more than 2,000 feet of topographic relief in Virginia. ("Relief" is the difference in elevation between the top of a mountain and the bottom of the adjacent valley.) From a distance, the mountains in the western states offer a dramatic contrast to the flat valleys/plains at their base. The Rocky Mountains rise thousands of feet from the Great Plains, and Mount Whitney in California offers 14,000 feet of relief between its peak vs. Death Valley.
Tourism officials make the most of the remaining topographic relief in the state, highlighting scenic mountain vistas and cool summer nights in the mountains. The Appalachian Trail is aligned to follow the ridgelines of Virginia mountains, so the views can be spectacular. (You could s-t-r-e-t-c-h the standard explanation of Virginia topography a little further. If you think in terms of tectonic plates rather than continents, Virginia could be described as reaching not just from sea level, but from the Abyssal Plain of the deep Atlantic Ocean to the top of Mount Rogers.)
The eastern side of Virginia, bordered by the Chesapeake Bay and Atlantic Ocean, is relatively flat. The mountains are concentrated on the west side of the state. Why is Virginia not completely flat, or completely mountainous? Virginia is relatively flat for the same reason that the state has only two natural lakes: after 200 million years of erosion, the land has been worn down.
At one time, 200 million years ago after Africa had collided with North America, Virginia had mountains that would have rivaled the Alps or Himalayas. Since then, rain, wind and gravity have transported the rocks down, down, downhill. Differential erosion (and some recent uplift) has left Virginia some remaining minor "ups and downs" with cliffs and waterfalls, but don't come to Virginia to climb 14,000-foot mountains. Virginia's landscape is too old, too eroded, too worn out. To climb tall peaks, go west where the Rocky Mountains are only 65 million years old. The tall mountains and natural lakes in the western states have not been drained by their outlet streams yet - but the time will come when the Rockies are as old as the Appalachians, and the relief will be much less.
The high parts of Virginia are still being eroded away; the solid earth is moving. Southwestern Virginia is washing downstream towards the Gulf of Mexico, as the tributaries of the Tennessee River and the New River carve away at the Appalachian Plateau and carry sediments downstream. The tributaries of the Potomac, Rappahannock, York, James, and Roanoke rivers are carrying Virginia's mountains to the Atlantic Ocean.
Rain carries sediments down hillsides into valleys, and sediments accumulate in the valleys until rivers carry the soil particles further downstream. The Blue Ridge in Shenandoah National Park is eroding today at roughly 20 meters per million years. If that is an average rate since the Appalachian Orogeny 200 million years ago, then 14,000 feet of the mountains in Virginia at the end of the Paleozoic Era could have washed away. Erosion may have been faster when the mountains were higher - other studies report erosion at 30 meters/million years in the Great Smoky Mountains, and up to 54 meters/million years in the in Susquehanna River basin.5 Today the granite "roots" of those ancestral Appalachians (such as the Vulcan quarry in Occoquan, or the granite rapids in the James River in Richmond) provide the best evidence of the old mountains that once stood on the eastern edge of the Piedmont, where traffic now races down I-95.
Virginia's valleys are eroding now, just as the mountains are wearing away and getting lower over time. Rainfall after each storm carries some of Virginia down towards sea level. after every rainstorm, muddy water running off every parking lot transports sediment downstream to the drain, mimicking the "carry me down to sea level" effect of erosion across the state.
One issue debated by geologists: are the mountains and valleys of Virginia in "dynamic equilibrium" and eroding at the same rate? If Virginia's mountains are eroding faster than the valleys, then Virginia will appear to get flatter and flatter over time and relief will disappear, until the state is a flat, topographically boring peneplain. However, if Virginia's valleys are being excavated faster than new sediments are eroding from hillsides and re-filling the valleys, then topographic relief in Virginia will increase as valleys get eroded lower at a rate faster than adjacent mountains.
Various studies, using different techniques, do not provide a simple answer for all mountain ranges. In some places, the pattern is clear. In the Basin and Range province of Nevada, sediments are accumulating in valleys so fast the mountain ranges are being buried - while in the valleys of Vermont, rivers are removing valley sediments at least as fast as the soil is washing down the mountains.
For the central Apalachians, sediments on the continental shelf of the Atlantic Ocean provide evidence of increased erosion in the last 3-4 million years - but where did those sediments come from? Climate changes during the Quaternary Era (including multiple ice ages) may have increased removal of valley sediments faster than mountain slopes eroded.6 If that is the case, then the topographic relief between valley floors and mountain tops increased, and it would appear the mountains of Virginia have grown more impressive.
Though Virginia's topographic relief is not great compared to the western United States, the Blue Ridge and the Appalachians still affected the travel routes of the Native Americans and served as a barrier to European settlement in the 1700's. The physical geography helped shape the boundaries of cultural regions and county boundaries, and of course the path of canals, railroads, and modern highways.
Eastern Virginia is so flat, the European settlers who arrived at the Atlantic shoreline were able to migrate westward with few physical limits for 100 years - until they reached the Blue Ridge. The 1,000-foot climb up through the gaps in the Blue Ridge was a significant barrier to travel from eastern Virginia into the Shenandoah Valley. Until the 1900's, most vehicles struggling up the mountain roads were one-horsepower wagons.
In contrast, European settlers coming from the Philadelphia region could access the Shenandoah Valley through an easier route, without the mountain climb. Starting in the 1730's, the Pennsylvania "Dutch" along with the Scotch-Irish moved into the Shenandoah Valley from the north. Today, the Amish, Menonnites, and Dunkers in Virginia are still concentrated west of the Blue Ridge, reflecting that historical migration in the mid-1700's.
The Europeans who first settled in the Shenandoah Valley were different from the Europeans who first settled in Tidewater. Differences in agricultural crops, the extent of slavery, and even the shape of the barns between Tidewater and the Shenandoah Valley can be traced back to the initial settlement pattern, and that pattern was shaped by the topography. There is a clear link between physical and cultural geography.
immigrants moving west from
the Chesapeake Bay had to
climb up/over the Blue Ridge
Fort Valley between the exposed flanks of the Massanutten Mountain syncline,
in the Shenandoah Valley between the Blue Ridge and West Virginia
(can you identify where the forks of the Shenandoah River merge,
after flowing northward on either side of Massanutten?)
erosion + time =
looking from Butt Mountain towards the Narrows in Giles County