the Tennessee-Virginia border today has evolved from the 36° 30' parallel of latitude defined in 1665 to separate Virginia-North Carolina
Source: ESRI, ArcGIS Online
The modern Virginia-Tennessee boundary line was surveyed originally as a border between North Carolina and Virginia.
Tennessee officials were not involved in making the first boundary surveys because there was no State of Tennessee until 1796, when the western part of North Carolina became a new state. Tennessee officials had their greatest impact on the Virginia-Tennessee border in 1802, and then later lawsuits and political compromises finalized the straight lines, notches and zig-zags in the boundary.
The first key decision shaping the modern Virginia-Tennessee border was made in 1629. King Charles I initially gave all the land between the 31° and the 36° parallel of latitude to his Attorney General, Sir Robert Heath, and named it Carolana. In 1645 during the English Civil War, Parliament revoked the grant and Heath died in exile.
Sir Robert Heath's claim to Carolana disappeared, but the boundaries defined in the 1629 patent were still remembered. In 1663, Charles II re-started the distribution of land by royal fiat by granting the Charter of Carolina to reward eight supporters who helped him during the English Civil War.
the Tennessee-Virginia border started as the 1629 boundaries of the grant of Carolana between the 31° and the 36° parallel of latitude to Sir Robert Heath
Source: ESRI, ArcGIS Online
In 1665, Charles II modified the North Carolina charter to grant the new colony control over all of the Albemarle Sound by moving the boundary a half-degree of latitude (approximately 34 miles) north to the 36° 30' parallel. In theory, the Virginia/Tennessee border was supposed to follow the westward extension of that 1665 boundary, the 36° 30' parallel of latitude separating Virginia from North Carolina.
Surveyors first started to mark a line along that 36° 30' parallel in 1710. Defining the boundary would clarify which colony could sell land and collect taxes there. The planned survey project failed completely. North Carolina's Edward Moseley accused the Virginia surveyors of using inaccurate instruments, and the Virginians accused Moseley of a conflict of interest as he speculated in lands along the border. Both sides were correct.
The "dividing line" survey of 1728 was more successful, and well-documented by William Byrd II in public and private records. That survey marked the boundary between Virginia-North Carolina from the Atlantic Ocean inland, going all the way to what the Virginians called the Dan River and the Carolinians called the Fitzwilliam River. The Virginians thought settlement would expand westward and surveyed all the way to Peters Creek. The North Carolinians quit earlier, claiming there was no reason to push the line so far west of existing settlements.
In 1749, Peter Jefferson and Joshua Fry surveyed another 90 miles west from Peters Creek. The instruments used by Fry and Jefferson in 1749 were imperfect. Accounting for the variation of magnetic north required constant refinement as the surveys moved westward. Fry and Jefferson drifted nearly five miles north of the 36° 30' parallel of latitude. The tilt of their survey line becomes more obvious as the line moves further west.
perhaps due to incorrect adjustments for magnetic declination, Fry and Jefferson's survey line tilted towards the north as they moved westward in 1749
Source: ESRI, ArcGIS Online
The Virginia surveyors stopped at Steep Rock Creek, a tributary of Holston River east of the modern town of Damascus. That location, the western point of the 1749 North Carolina-Virginia colonial boundary line, may be the stream known today as Laurel Creek.
the 1749 survey of the Virginia-North Carolina border stopped at Steep Rock Creek (probably modern Laurel Creek)
Source: Library of Congress, A map of the most inhabited part of Virginia containing the whole province of Maryland with part of Pensilvania, New Jersey and North Carolina. (drawn by Joshua Fry & Peter Jefferson in 1751)
the end of the 1749 survey by Peter Jefferson and Joshua Fry at Steep Rock Creek (red circle)
Source: ESRI, ArcGIS Online
The rest of today's Virginia-Tennessee boundary was defined after Virginia declared independence from England in 1776 and became a state, and there were multiple and conflicting surveys before final resolution. After North Carolina ceded its western lands to the Continental Congress, Virginia disputed the boundary with the Federal government (which controlled the Southwest Territory) and finally Tenneesee after it became a state.
For two decades after 1749, the colonies of Virginia and North Carolina had no reason to extend the boundary from its ending at Steep Rock Creek. Settlement in the western edges of the colonies was slowed by the distance from the port cities on the Eastern seaboard, and by resistance from the Cherokees.
A major stimulus for clarifying the colonial boundaries beyond the Blue Ridge was the British victory in the French and Indian War, followed by the decision of the British government to ban settlement in the watersheds of the Ohio and Tennessee rivers west of the Eastern Continental Divide.
The Treaty of Paris in 1763 increased security on the borderlands west of the Appalachian mountains. Military success removed the French from those regions, ending their ability to supply weapons and help Native Americans fight the English, but expelling the French had been expensive.
Virginia land speculators, including the Ohio Company and Loyal Land Company, benefitted from the victory. In London, officials expected the colonists to be grateful and to be willing to help repay the costs of the war.
Great Britain borrowed money to pay for the Seven Years War (known as the French and Indian War in Virginia, where the longer conflict lasted from 1754-1763). The two obvious ways to repay the debt were to 1) increase revenue and 2) reduce the cost of government, especially reduce costs for military forces in North America after defeat of the French.
Proposals to increase revenue including imposing new taxes on the North American colonists. The 13 colonies had benefited immensely from the decisions in London to send warships and troops from Britain to seize the Ohio River Valley and Canada, so London officials thought the colonies should help repay at least a portion of the debt.
The colonists did not view the situation the same way as officials in London. Leaders in Virginia and other colonies failed to acknowledge the benefits of raising colonial taxes to repay the costs of providing the imperial "redcoats" who had provided better border security.
Colonial leaders were more than just ungrateful, selfish beneficiaries of English military power. Most officials in the colonies were Americanized by the 1760's, focused on how the colonies would evolve in the imperial system. Their priority was not assisting an island across the Atlantic Ocean to extract wealth from its colonies.
The colonial leaders objected to new taxes in part because they were looking forward with an eye on future risks, not backward at accomplishments. Direct taxation, without representation in Parliament, meant there was no effective way to limit future increases in imperial taxes through the political process. The precedent of repaying Britain for the costs of the French and Indian War could lead to ever-increasing taxes on Americans, taxes that could squeeze the colonists to fund the costs of maintaining/expanding an empire in Ireland, India, and elsewhere.
To accommodate American objections, London officials proposed different taxes. Colonists resisted them all. That resistance led to the Stamp Act crisis in 1765, the Boston Tea Party in 1771, and ultimately the American Revolution in 1775.
The efforts to reduce costs of government led to the Proclamation of 1763 by King George III. It established a "proclamation line," a boundary with colonists on the easternside and an Indian Reserve on the western side. The proclamation meant that colonists could no longer move west, settle on lands claimed by Native Americans, and then get help from the colonial governments to respond to the inevitable attacks.
The Proclamation Line of 1763 was intended to reduce the costs of maintaining British military forces on the western frontier of the colonies by minimizing settler-Native American conflicts. When settlers encroached onto lands claimed by Native American tribes, they fought back through raids and military action often called "massacres" by the colonists.
Despite the loss of French support, Shawnee and Cherokee warriors continued to resist trespass onto their hunting grounds in the watersheds of the Ohio, Kentucky, and Tennessee rivers. Raiders burned cabins and killed families on the western edge of the Carolinas, Virginia, Pennsylvania, and New York. Pontiac's Rebellion in 1763 made clear that colonial claims to the Ohio Country, based on charters issued in England and land warrants issued in Williamsburg, were not accepted by the current residents.
Colonists organized their own incursions that killed Native Americans, cut down cornfields, destroyed villages, and spurred yet another round of retaliation. There was no political or judicial process to resolve the conflicts, and outfitting the militia or sending imperial troops into the backcountry was expensive.
the defeat of the French and the 1763 Treaty of Paris triggered a need to define the Virginia-North Carolina boundary west of the Blue Ridge
Source: Library of Congress, Map Showing Imperial Context in North America before the 1763 Treaty of Paris
The obvious solution, at least as officials in London viewed the situation, was to separate the two sides.
Britain expected the Proclamation of 1763 to lead to treaties with the Native Americans that defined boundary lines, limited new colonial settlement to lands that had been ceded by the Native Americans to the colonies, and minimized warfare. Reducing Native American-settler conflicts by separating the two groups would limit the number of troops required to protect colonists from Native American raids, and would reduce the costs of negotiating peace treaties on the western edge of English settlement in North America.
In the Proclamation of 1763, British officials created an Indian Reserve for the newly-acquired lands west of the Appalachian Mountains. The declaration blocked the representative assemblies and governors in the colonies from issuing land grants in the portion of western North Carolina and Virginia within the Ohio River watershed. The Proclamation Line created a "colonial growth boundary," one that would block settlement of territory of great interest to land speculators with influence in Williamsburg.
the Proclamation of 1763 was intended to establish an Indian Reserve to keep settlers and Native Americans apart, reducing the costs for military protection
Source: Wikipedia, Proclamation of 1763
The next step after issuing the proclamation was for British officials to negotiate with different tribes. Treaties would define what lands would still be controlled by Native American groups, what territory would be ceded to Britain, and how the boundaries would be marked.
In 1768, British and colonial officials arranged for a peace treaty between the Iroquois and the Cherokee. The goal was to stop the traditional long-distance raids by those two nations through territory which the British planned to acquire from each Native American nation. Peace between the Iroquois and the Cherokee would minimize raids that could involve settlers on the western edges of the colonies.
British officials negotiated the 1768 Treaty of Hard Labor with the Cherokee. They agreed to relinquish their rights to territory south of the Ohio River and east of the Kanawha River, including about half of modern West Virginia.
Also in 1768, the Iroquois signed the Treaty of Fort Stanwix. They abandoned claims to the territory south of the Ohio River, all the way downstream to the mouth of the Tennessee River. The Iroquois had no settlements in that region and thin justification for asserting control over it, but the British used the 1768 Treaty of Fort Stanwix to clear Iroquois title to lands in western New York as well as south of the Ohio River.
The Cherokee recognized that the 1768 Treaty of Hard Labor would not define a final boundary, because settlers were already living west of that line. Two years later, the Cherokee ceded more land in the 1770 Treaty of Lochaber. That moved the boundary further west, authorizing occupation of additional territory in the New River and Holston River valleys north of the Virginia-Carolina border.
The Cherokee would not agree to surrender their settlement on Long Island in the Holston River, but in the 1770 Treaty of Lochaber they moved the boundary line westward from the line drawn in the 1768 Treaty of Hard Labor to a point just six miles away from Long Island.
extending the 1749 survey of the southern boundary of Virginia was triggered by increased settlement on the frontier and treaties with the Cherokee/Iroquois to clear title to lands in the Holston River valley
Source: National Park Service, 1768 Boundary Line Treaty Map
Anthony Bledsoe did an initial survey in 1771 that had no legal basis, but revealed the Virginia-North Carolina boundary was north of the settlements on the South Fork of the Holton River. Later in 1771, John Donelson surveyed the new boundary between British and Cherokee lands.
Anthony Bledsoe surveyed to Beaver Creek in 1771, identifying that settlements in the Holston River valley were south of the Virginia-North Carolina boundary
Source: ESRI, ArcGIS Online
Donelson's Line did not follow the terms negotiated in the 1770 Treaty of Lochaber. Most significantly, he ignored the provision in the 1768 and 1770 treaties that defined the mouth of the Kanawha River as the northern end of the ceded lands, and defined a line northwest to the confluence of the Kentucky and Ohio rivers. The Cherokee accepted the adjustment, but the shift to the Kentucky River was not formalized in any paperwork that might be seen by officials in Williamsburg or London.
Donelson altered the southern boundary as well, knowing that the Virginia-Carolina border at 36° 30' parallel of latitude was located north of many farms already established by early settlers. The Cherokee agreed to move the line south to follow the South Fork of the Holston River rather than require the survey along the actual boundary, to a point on the South Fork of the Holston River located six miles east of Long Island.
the 1768 Treaty of Hard Labor and 1770 Treaty of Lochaber expanded the territory where settlement was permitted, and Donelson's Line (shown in green, above) gave Virginia control over land south of the 36° 30' parallel of latitude
Map Source: ESRI, ArcGIS Online
That southern adjustment authorized the settlement at Sapling Grove. It is now developed into the cities of Bristol, Virginia and Bristol, Tennessee.
The Cherokee also agreed to allow settlements further south of the Donelson Line, when they signed the 1775 Treaty of Sycamore Shoals with Richard Henderson and negotiated a deal with those already living on the Watauga River.1
John Donelson's 1771 survey altered terms of the Treaty of Lochaber to legitimize existing settlements south of the Virginia-Carolina border and north of the South Hoston River
Source: Discover Kingsport, Maps: Kingsport
The population on the southwestern frontier had increased after the French and Indian War ended in 1763. Virginia needed to determined to define the border in order to exert control over its territory after the 1768 and 1770 treaties, rather than leave settlers "in a state of nature" without effective government. Land speculators exacerbated the confusion when they tried to establish independent governments and then collect revenue from sale of the land claimed by Virginia.
Population growth in southwestern Virginia triggered the colony to create new counties. The General Assembly divided Augusta County in 1770, forming Botetourt County from its southern half.
In 1772, the General Assembly created Fincastle County out of Botetourt County. Squatters may not have worried about legal land titles, but knowing the location of the Virginia-Carolina border was essential for settlers planning to purchase land on the frontier in the 1770's. Land surveys had to be completed by authorized county surveyors and filed in the appropriate county courthouse to establish ownership.
Settlers planning to purchase the land they were improving wanted to know which government's land warrants were valid, and where to file their surveys. Legal ownership required knowing whether Virginia or North Carolina courts would resolve land disputes. Colonial and later state officials were also interested in a clear boundary, in order to receive the appropriate revenue from lands sold to settlers.
Fincastle County was created in 1772
Source: Library of Virginia, Fincastle County
Efforts to establish the Virginia-North Carolina boundary were renewed during the American Revolution, despite the disruption of British invasions of Virginia via the Chesapeake Bay. "Land hunger" by settlers in the upper Tenneesee River watersheds led to conflict with Native American tribes, especially Cherokee and Shawnee who sided with the British, but in 1775 there was no guarantee that the settlers would choose to fight for independence.
In the 1775 Treaty of Sycamore Shoals, Richard Henderson and other land speculators tried to bypass the colonial governments east of the Blue Ridge and create their own government of Transylvania. Henderson's Transylvania Company purchased whatever rights the Cherokees had to 20 million acres of land between the Kentucky and Cumberland rivers, plus a Path Deed to provide access to the territory west of the Cumberland Mountains. The Watauga Association negotiated its own deal with the Cherokee to occupy lands south of the Donelson Line, but a deed from Virginia to parcels south of the latitude of 36° 30' had questionable legitimacy.
The new state governments had to ensure there was a process for acquiring clear title to land, if the settlers were expected to fight for the American side in the Revolutionary War. State officials recognized that they had to define the location of the Virginia-North Carolina border, and organize county governments which could confirm land titles.
In 1776, the General Assembly divided Fincastle County into Montgomery, Washington, and Kentucky counties. The 1776 election in Washington County for delegates to the House of Delegates was disputed by the losers, Arthur Campbell and William Edmiston. They claimed the winners, Anthony Bledsoe and William Cocke, had been elected with the help of voters who lived in North Carolina rather than in Virginia.
The General Assembly rejected the argument and allowed Anthony Bledsoe and William Cocke to serve. In 1777, Anthony Bledsoe was re-elected and Arthur Campbell joined him as a delegate. Bledsoe led the effort to have the Fry-Jefferson boundary extended west from Steep Rock Creek. William Cocke, once he was no longer a delgate, claimed he lived in North Carolina and refused to pay Virginia taxes.2
between 1775-1785, settlers in western Virginia and North Carolina proposed multiple solutions to creating local governments not dominated by Tidewater planters
Source: Atlas of the Historical Geography of the United States, Colonies or States Proposed or Organized by Settlers West of the Allegheny Mountains, 1775-1785 (Plate 41c, digitized by University of Richmond)
As a result, during the middle of the American Revolution in 1779 Virginia and North Carolina agreed on a new boundary survey. The project, requiring state resources far to the west of fighting with the British, reflected the demand for legally-defensible land titles on the edge of settlement.
The decision came thirty years after Fry and Jefferson had stopped at Steep Rock Creek. Virginia and North Carolina still claimed lands west to the Mississippi River, based on their ancient colonial charters. In 1779 neither state had relinquished its western land claims to the Continental Congress, and it would be over a decade before the states of Tennessee and Kentucky would be created.
Virginia and North Carolina appointed surveyors and commissioners to mark their joint boundary once again in 1779. Virginia was represented by Dr. Thomas Walker and General Daniel Smith, while Colonel Richard Henderson, William Bailey Smith, and John Williams represented North Carolina.
the 1755 John Mitchell map showed Thomas Walker's cabin, built on the Cumberland River in 1750 as he explored beyond the Cumberland Gap for the Loyal Land Company - and the end point of the 1749 survey "336 miles from the sea"
Source: Library of Congress, John Mitchell, A map of the British and French dominions
in North America, with the roads, distances, limits, and extent of the settlements
Both teams had representatives with strong personal agendas. Walker was active in the Loyal Land Company, with a grant from Virginia for 800,000 acres in southwestern Virginia. Henderson was the prime mover behind the Transylvania effort, through which he had hoped to acquire title to 20 million acres in the Kentucky region of Virginia.
the 36° 30' boundary established in the 1665 charter was supposed to be extended westward by the 1779-80 survey
Source: Library of Congress, Partie occidentale de la Virginie, Pensylvanie, Maryland, et Caroline (1781)
The 1779 survey started at Steep Rock Creek, but the commissioners and surveyors could not find the point where Peter Jefferson and Joshua Fry stopped in 1749. The marks they had made on trees to define the boundary line 30 years earlier had been healed by new growth.
The two survey teams agreed to begin the new survey by defining the latitude of 36° 30' and choosing a new point of beginning. From the point of beginning, the team of Carolina and Virginia surveyors moved west into the upper Holston River valley. After 45 miles of moving west, the surveyors reached Carters Valley near modern-day Kingsport, Tennessee. There, the North Carolinians concluded that the line being surveyed was two miles to the south of 36° 30' and moved north to start a new survey line.3
Walker and the Virginia surveyors ignored the objections of the North Carolinians and kept blazing the "Walker Line" to the west. In hopes of resolving the disagreement, one Virginia commissioner, General Daniel Smith moved north two miles and surveyed back towards Steep Rock Creek.
Smith concluded halfway back that he had made a mistake and the original line was correct. He rejoined Walker, after writing in his diary:4
The North Carolina surveyors reached their starting point, started again, and marked a separate "Henderson Line" from Steep Rock Creek to Cumberland Mountain. The North Carolina representatives stopped at Cumberland Mountain and went home, but the Virginia team kept surveying to the west.
As a result of the disagreement, the two sets of surveyors created two lines, separated by a two-mile gap, for over 100 miles between Steep Rock Creek and Cumberland Gap. North Carolina surveyors defined the Henderson Line on the north, while Virginia surveyors marked the Walker Line on the south. In this two-mile "gore" of unclear ownership, legal authority was unclear and neither state could collect taxes effectively.5
Walker, Smith and the Virginia surveyors kept surveying west beyond the Cumberland Gap. At Deer Fork, 124 miles west of their starting point at Steep Rock Creek, the Virginians skipped ahead 109 miles to the Cumberland River. There they determined through astronomical observations the latitude of 36 degrees 30 minutes, and surveyed 41 more miles west to the Tennessee River. At the river, they ended up being over 17 miles north of the desired 36° 30'. The error would have benefited North Carolina, had that state's commissioners/surveyors stayed with the project.6
As Virginia and North Carolina committed to establish legal land claims by initiating the boundary survey, a critical number of settlers on the western edge of the states chose to fight for independence. In 1780 the "Overmountain Men" marched across the Blue Ridge and helped defeat the Loyalists, led by Major Patrick Ferguson, at the Battle of King's Mountain.
In 1784, after the American Revolution ended, North Carolina made an initial cession of its western lands to the Congress. The cession was rescinded, and several North Carolina counties west of the Blue Ridge petitioned the new Congress to admit them as the State of Franklin. Congress rejected the proposed 14th state, and ultimately Virginia and North Carolina each gave Henderson 200,000 acres to eliminate his claim and "quiet the title" to land grants.
In 1790, North Carolina finally relinquished its western land claims and the new Federal government created the Southwest Territory. Much of southwestern Virginia became the State of Kentucky in 1792, and the Virginia-Southwest Territory border stretching west of Cumberland Gap became the Kentucky-Southwest Territory border.
Virginia was bordered by the Southwestern Territory between 1790-96, after North Carolina ceded its western lands to the national government and before the State of Tennessee was accepted into the Union
Source: Library of Congress, Map of the state of Kentucky: with the adjoining territories, 1795
Congress converted the Southwest Territory into the new state of Tennessee in 1796. The zig-zag boundary between the 1749 survey's end point and the 1779 survey's point of beginning, the Virginia-North Carolina boundary between 1779- 1790 and the Virginia-Southwest Territory boundary between 1790-1796, became today's Virginia-Tennessee boundary.
the current Tennessee-Virginia boundary is out of alignment with the North Carolina-Virginia corner because the 1779 Walker Line survey started northeast of Steep Rock Creek, where Joshua Fry and Peter Jefferson had stopped in 1749
Source: ESRI, ArcGIS Online
The debate about how to resolve the disputed Virginia-North Carolina boundary on its western end continued after creation of the independent states of Kentucky and Tennessee. According to the 1665 grant by King Charles II, the Virginia-Tennessee border and the Kentucky-Tennessee border should match the 36° 30' parallel of latitude.
The actual border is based on the inadequate expertise and equipment of the 18th Century, political compromises, and lawsuits.
At its western end the Walker Line was located almost 10 miles north of the intended latitude, and Kentucky lost territory to Tennessee due to the errors. In 1820, Kentucky accepted the Walker Line as its boundary, but Tennessee gave Kentucky title to all the vacant land between 36° 30' and the Walker Line.
The two states also agreed to move the boundary between the Tennessee-Mississippi rivers, after the Jackson Purchase extinguished the claim of the Chickasaws to that territory. The Walker Line, which had veered too far north, had stopped at the Tennessee River. West of that natural feature, Kentucky and Tennessee adopted the 36° 30' parallel as their boundary, as surveyed in 1819 by Robert Alexander and Luke Munsell.7
the Kentucky-Tennessee border was adjusted west of the Tennessee River to mitigate for errors made by the 1779-80 Walker Line survey
Source: ESRI, ArcGIS Online
Joshua Fry and Peter Jefferson displayed the Virginia-Carolina border as a straight east-west line at 36° 30'
Source: Library of Congress, A map of the most inhabited part of Virginia containing the whole province of Maryland with part of Pensilvania, New Jersey and North Carolina
The actual boundary is defined by on-the-ground marks and monuments - physical indications such as blazes on trees or stones placed into the earth - that were made by the surveyors. The ability of Global Positioning System (GPS) and Geographic Information System (GIS) technology to define the 36° 30' parallel more accurately is irrelevant in modern land ownership disputes.
Pioneer surveyors dragged iron chains west from the Atlantic Ocean, cutting a path through the natural vegetation and documenting the bearings/distances between monuments. In legal disputes since then, the monuments set on the ground are almost always defined as the property boundaries, no matter what documents may have said were supposed to be the dividing lines between colonies/states.
The southern boundary line of Virginia with Tennessee has curves and notches. The reasons for the shifts in the Virginia-Tennessee border are not clear. Suppositions include the effect on instruments of iron deposits in the Iron Mountains, in addition to the traditional tales about hard-drinking surveyors losing their sense of direction and strong-willed landowners convincing the surveyors to avoid cutting through pre-existing parcel boundaries.
One author concluded that many of the explanations for the adjustments were just made-up tales, and the most likely reason is that landowners requested boundary adjustments in order to keep their property in one state or the other. In his opinion, the large notch between North Carolina and Bristol was:8
In 1802, Virginia and Tennessee agreed to survey a compromise boundary; each state would be given half the territory between the Henderson Line and the Walker Line. The Compromise Line of 1802 was surveyed from Whitetop Mountain to Cumberland Gap.
Commissioners for Virginia were Joseph Martin, Creed Taylor, and Peter Johnston. Commissioners for Tennessee were General John Sevier, Moses Fisk, and General Joseph Rutledge, and surveyors were Brice Martin and Nathan Markland. Martin and Markland marked blazes in a diamond pattern, so that 1802 survey is known as the "diamond line."9
diamond blaze of 1802 survey
At Cumberland Gap, Virginia's southwestern tip, there is a jog in the three state boundaries. The Virginia/Tennessee boundary is based on the 1802 compromise between the Walker/Henderson lines. The Kentucky-Tennessee line is located further south, based on the Walker Line.10
the Virginia/Tennessee and Virginia/Kentucky boundaries are not aligned at Cumberland Gap
Source: ESRI, ArcGIS Online)
Virginia tried to re-open the question of its boundary with Tennessee in 1858, 1870, and then again in 1887. Tennessee insisted on keeping the 1802 compromise line, so the states ended up settling their boundary through a lawsuit.
Tennessee won the case. In 1893, the Supreme Court ruled in Virginia v. Tennessee:11
looking east from Cumberland Gap
The Supreme Court decision confirmed that the long-accepted line would stay the boundary, even if the charter had defined a different line.
In Virginia's dispute with Maryland over the boundary along the Potomac River, Virginia had argued that long acceptance of the low-water mark should make it the boundary. Altering the boundary to the technically-correct high-water mark would be too disruptive.
Virginia lost its claim to land in Tennessee by the same rationale. Election districts, tax assessments, and real estate records would not have to be adjusted because the Supreme Court ruled in 1893:
in 1893, the Supreme Court rejected Virginia's attempt to move the Tennessee boundary
Source: Atlas of the Historical Geography of the United States, Virginia-Tennessee Boundary (Plate 99a) digitized by University of Richmond
The court case did clarify the origin of the mysterious notch in the boundary between Tennessee and Virginia in the Blue Ridge. In width the notch extends for over 15 miles, and is about 1.5 miles wide. On the Virginia side is Washington County, and on the Tennessee side are Sullivan and Johnson counties.
When the 1802 line was resurveyed in 1901, the commissioners (who also served as the surveyors, in order to minimize cost) explored east and west of the notch. They looked for blazes on trees in case the Diamond Line surveyors had surveyed a straight boundary between the Holston River and Steep Rock Creek in 1802, before creating their final notch through the Blue Ridge.
The 1901 surveyors were able to find the distinctive diamond blazes from 1802. They found other markings remaining from an 1858 survey, when Virginia tried to re-open the boundary question. However, no marks were found on trees east or west of the notch that varied from the 1802 surveyors. The notch in the 1802 Diamond Line survey reflected the original field work.12
Apparently the 1802 surveyors chose to use the Henderson Line through the Blue Ridge. When Henderson split from Walker, he had surveyed east to Burnt Hill. That endpoint was south of Whitetop Mountain, over one mile north and roughly two miles east of the spot where Fry and Jefferson had stopped their survey at Steep Rock Creek in 1749.
The Virginians on the 1802 compromise survey could have demanded that the starting point be located further south, closer to the latitude of 36° 30'. Burnt Hill was convenient because the hillside was clear of timber, and there were few obstructions for surveyors using line-of-sight tools to mark points.
The 1802 decision to use Burnt Hill as the eastern end of the Diamond Line created a zig-zag boundary. The zig-zag was required to connect the eastern end of the compromise boundary line to the western point where Joshua Fry and Peter Jefferson stopped in 1749.
the 1802 survey known as the Diamond Line created created a zig-zag in the Virginia-North Carolina border
Source: US Geological Survey (USGS), Grayson 1:24,000 topographic quadrangle
The 1802 Diamond Line surveyors used the Henderson Line only through the Blue Ridge. They angled south to the compromise latitude, once they reached river bottoms of greater value in the Holston Valley. The notch in the border serves as a large offset through the mountains. North Carolina gained acreage in the notch, but the Blue Ridge land was steep and of little value for farming.
the 1802 Diamond Line created a notch in the boundary through the Blue Ridge, simplifying the survey challenge and giving North Carolina additional acreage until reaching the higher-value lands in the Holston Valley
Source: ESRI, ArcGIS Online
The 1802 survey report says they started "on the summit of the mountain generally known as the White Top mountain." The 1901 surveyors were confident that the 1802 effort had started from Burnt Hill, and chose to define that spot as the northeast corner of Virginia/Tennessee.
Tennessee-Virginia border, with notch east of Bristol
Source: National Atlas
Virginia did manage to convince Tennessee to make one adjustment in 1901. The 1802 Diamond Line ran through Bristol, which had developed on both sides of the state boundary. (The Virginia side was originally the community of Goodson.) The state line was moved, in a bi-state agreement ratified by the US Congress, from the sidewalk on the northern side of the main street to the middle of the street.
This occurred after the "Water Works War of 1889." That dispute was triggered when a Tennessee-based water company tried to extend its lines to serve customers in Virginia. A Virginia-based officer arrested the company president as he was working on the project. The Virginia-based utility then tried to construct its own pipeline down Main Street. Sheriffs from both Tennessee and Virginia brought their deputies to the scene, and the Tennessee sheriff raised a posse comitatus of several hundred volunteers.
Though violence was a real possibility, the "war" ended in a scene worthy of a Charlie Chaplin comedy episode. The Tennessee sheriff tried to serve a warrant on the Virginia officer who had arrested the president of the Tennessee company. The officer squirmed away, fell into the pipeline ditch - and the sheriff fell in on top of him. Another officer defused the situation, inviting them both to get up and go home until the lawyers could sort it out.13
the Virginia-Tennessee-Kentucky border is marked at Cumberland Gap National Historical Park
presumed NC-VA border, 1779 (assuming a straight line...)
Source: History of the South Carolina cession, and the Northern boundary of Tennessee by William Robertson Garrett (p.2)
the boundary between Virginia and North Carolina was not defined until the American Revolution, the boundary between Kentucky-Tennessee was not finalized until 1820 - and Virginia disputed its boundary with Tennessee until 1893
Source: Library of Congress, North America, and the West Indies; a new map, wherein the British Empire and its limits, according to the definitive treaty of peace, in 1763, are accurately described (Carington Bowles, c.1774)
mapmakers as late as 1796 showed a Virginia-Tennessee border extending straight to the Cumberland Mountains, based on the 36° 30' parallel of latitude defined in 1665 to separate Virginia-North Carolina
Source: Library of Congress, A map of the United States exhibiting post roads & distances : the first sheet comprehending the nine northern states, with parts of Virginia and the territory north of Ohio (1796)
the western lands ceded by North Carolina were organized as the Southwest Territory, until Tennessee was admitted into the Union
Source: Atlas of the Historical Geography of the United States, States, Territories, and Cities, 1790 (Plate 61e) and Colonial Towns, 1775 (Plate 61d) digitized by University of Richmond
in 1897, the Holston River had not yet been dammed and flowed freely across the Tennessee-Virginia border
Source: US Geological Survey (USGS), Bristol 1:250,000 topographic quadrangle (1897)
(from ESRI USGS Historical Topographic Map Explorer)