The best evidence still suggests that the ancestors of the first immigrants to Virginia crossed the Bering land bridge about 15,000 years ago - though it is possible that the Native Americans are descendants of people who paddled across the Atlantic Ocean and arrived from the east.
The traditional story is that Virginia was settled from the west, by hunter/gatherers who walked up river valleys. They crossed what we now call the Mississippi River and entered what we now call Virginia - long before there were kings or queens in England, long before anyone named Columbus sailed westward towards India, and long before we assigned the current names to places in North America.
While the original settlement of Virginia is still unclear, we know that European settlement into Tidewater and Piedmont Virginia came from the east.
In the Shenandoah Valley and the rest of the Valley and Ridge physiographic province, stretching to Cumberland Gap, most European settlement arrived from the north rather than the east, due to the barrier of the Blue Ridge.
Some settlers migrated south through the valleys west of the Blue Ridge crossed to the east side of the Blue Ridge at modern-day Roanoke, reaching the Piedmont west of Lynchburg. Some of the settlers who walked south through the Shenandoah Valley, then went east at the Roanoke River gap, kept moving south and occupied the Piedmont of North Carolina.
For example, Daniel Boone's family, and the Moravians who initially settled Winston-Salem, migrated through that gap at Roanoke on their way to the Yadkin River valley in North Carolina. Later, Boone explored westward, leading hunters and settlers through Cumberland Gap into Kentucky. The Great Wagon Road south of Roanoke was extended, becoming the Wilderness Road and (today) I-81.
As far back as the 1720's, Governor Spotswood purposefully encouraged settlement of the Shenandoah Valley by non-English immigrants. When Spottwood started serving as governor, the Piedmont (east of the Blue Ridge) was just being settled by immigrants from England. The English immigrants developed farms between the Fall Line and the Blue Ridge, but settlement was moving slowly upstream into the Piedmont and not sweeping westward over the Blue Ridge.
Spotswood feared the French were occupying lands just to the west of the Blue Ridge, moving down from Canada into the Ohio River Valley. If there was a war between France and England in European, that conflict could expand across the Atlantic Ocean. An attack by French and their Native American allies on the frontier settlements in English-controlled Virginia was a possibility that needed some sort of response from the colonial governor in Williamsburg.
Spotswood had bad maps. He thought the French forts on the Great Lakes were less than a 1-week march from the Blue Ridge. Governor Spotswood identified the most likely military threat to the western frontier of Virginia to be from the French in the Mississippi and Ohio River valleys, just as a century earlier the first colonists at Jamestown had considered the Spanish and other European rivals to be the most significant military threat. If the French forces in Canada and the Ohio River Valley allied with hostile tribes, they could block English settlement at the Blue Ridge - and even threaten settlements in the Piedmont.
The first European country to occupy lands between the Blue Ridge and the Ohio River would control that territory. Spotswood recruited Germans and Scotch-Irish who arrived at Philadelphia to settle in Virginia, between the Blue Ridge and the French. The first colonists to settle Virginia west of the Blue Ridge walked from Philadelphia into the Shenandoah Valley, where they established settlements that would serve as a buffer and a trip wire to alert the Virginians about western incursions. (Spotswood's concerns were validated in the 1750's, when settlements in the Valley and Ridge province from Winchester to the New River were attacked during the French and Indian War.)
Some English-descended colonists crossed the Blue Ridge from the east, settling in the Shenandoah Valley. The English-dominated eastern edge of Frederick County ultimately separated and became Clarke County, and the culture of the two counties is distinctly different even today. By the time the Anglicans from the east crossed the Blue Ridge, the culture of the Shenandoah Valley was already dominated by the Scotch-Irish and the Pennsylvania Deutsch ("Dutch") immigrants. The Scotch-Irish established Presbyterian churches. The Pennsylvania immigrants established Lutheran, Brethren, Dunker, and Mennonite churches.
European culture has spread completely across Virginia and the North American continent in the last 400 years. The "frontier" of settlement, the line between territory that was settled and land that was "unsettled" (except by Indians), was no longer obvious by the 1890 Census.
However, for the first 200 years of colonization, most of the immigrant (colonist...) population lived near the Atlantic Ocean. Settlers were slow to move inland from the Atlantic Ocean coast because ships could no longer provide easy transport for agricultural exports, once settlers moved further west past the Fall Line.
Half of all the people in America lived east of the new capital of Washington DC when it was founded in 1800. Transportation by wagon was far more expensive than shipping directly from a Tidewater wharf, so farmers living west of the Fall Line spent much of their "profit" on the cost of getting their goods to port cities such as Charleston, Alexandria, Baltimore, Philadelphia, and New York.
From 1810-1850, the "mean center of population" for the United States was located in Virginia. It moved from 39 degrees 11 minutes 30 seconds latitude, 77 degrees 37 minutes 12 seconds longitude in Loudoun County in 1810 to 38 degrees 59 minutes 00 seconds latitude, 81 degrees 19 minutes 00 seconds longitude near Parkersburg, Virginia (now West Virginia) in 1850. Only in 1860 did the center of population move west of Virginia, across the Ohio River.
There was no guarantee that English settlement to the west would be successful. (If you do believe in Manifest Destiny, how do you explain the failure of the Americans to settle Mexico and the prairies of Canada?) The French could have succeeded in occupying the Ohio River valley, establishing a line of settlements from New Orleans to Quebec and restricting the British to a strip on colonies along the Atlantic Ocean... but defeat in the Seven Years War ended the future of the French in North America.