Multiple colonial charters, two negotiated settlements by the states in 1785 and 1958, an Arbitration in 1877, and several Supreme Court decisions have defined how Maryland and Virginia would deal with the Potomac River as a boundary line and shaped the boundary on the Eastern Shore (separating Accomack County in Virginia from Worcester/Somerset counties in Maryland).
The Potomac River divides Maryland and Virginia, but Virginia does not own half of the Potomac River. The line separating Maryland from Virginia is not in the middle of the river; the Maryland-Virginia boundary is next to the Virginia shoreline.
 Potomac River boundary between MD and VA, showing St. Marys County line extending to Virginia shoreline Source: Terraserver |  Oops - this map is wrong. State boundary is not in the middle of the Potomac River Source: David Rumsey Library, The States of Maryland and Delaware, from the latest Surveys, 1795 |
As a result of this peculiar boundary, if you want to get married on a boat in the middle of the Potomac River while looking at Mount Vernon, you need a Maryland marriage license. In the 1950's, when slot machines iquor by the drink were legal in Maryland but not Virginia, Colonial Beach and Prince William County had slot machines located on boats docked in the river off the Virginia shoreline. Customers would park in Virginia, walk out a pier, and "step across the line" into Maryland.
Between 1606-1632, the Virginia colony included all what is now Maryland based on three charters issued by James I. In 1632, Charles I reduced the size of Virginia when he granted a charter to Cecil Calvert, Baron of Baltimore. The new colony was located north of the "River of Pattowmack...unto the further Bank of the said River."1 The Maryland grant extended from basically the 40 degree parallel south to the mouth of the Potomac (about the 38 degree parallel).
As part of the Maryland charter, Lord Calvert was specifically granted control down to the edge of the Potomac River on the Virginia shore. Where's the actual line of the "further Bank of the said River" (in Latin, ad ulterioram predicti fluminis ripam)? Until 1877, Maryland's legal control was assumed to be to the high water mark, basically where the vegetation ends and the shoreline of bare rock/sand/mud begins.
No one knows why the 1632 charter was so generous to Maryland - but Lord Calvert had political skills as well as a title. He named his colony "Maryland" after the wife of Charles I, Queen Henrietta Maria. (Similarly, the first English settlers who tried to establish a colony on the Outer Banks in 1584-87 named it after the "virgin" Queen Elizabeth, nearly 40 years earlier.)
Virginians were not legalistic about honoring the high-water mark being the boundary. George Washington, for example, operated a herring fishery in the Potomac River offshore from Mount Vernon. It provided a more-reliable source of income than growing tobacco and wheat, but he never asked for permission or paid Maryland anything for "their" fish.
Maryland fishermen objected to Virginians poaching from Maryland waters, and Maryland proposed to tax commercial traffic going to Virginia ports via the Potomac River. In its claim to the entire Potomac River and its fishery resources, Maryland could cite the colonial grant from Charles II.
By 1785, however, the colonies had successfully rebelled against the King of England. It was not clear how Maryland could enforce any claim based on the now-rejected authority of the English kings. In addition, the new nation was only a loose confederation, governed by a weak national Congress. The "United States in Congress Assembled," operating under the Articles of Confederation, might suport ancient land grant claims by Maryland... maybe. Maryland had refused to ratify the Articles of Confederation until 1781, requiring Virginia and other states to cede all claims to western lands to the new national government. Still, Virginia remained the largest, most-populated state in the new nation.
In 1785, it was unclear how the weak national government could force Virginia to comply with Maryland's interpretation of the 1632 charter. (At the time, there was no Supreme Court operating as an independent third branch of government.) Maryland had a claim from the king of England to the river... but not to the Chesapeake Bay south of the mouth of the Potomac River. Virginia, according to its royal charters, had the ability to tax Maryland shipping coming from the Atlantic Ocean into the Chesapeake Bay between Cape Charles and Cape Henry, and then sailing north to the mouth of the Potomac River. Each state could wreak economic havoc on the other.
The Virginia General Assembly appointed George Mason, Edmund Randolph, James Madison, and Alexander Henderson as commissioners to negotiate a compact. The compromise was led by George Washington, who arranged for two-state discussions in 1785 at Mount Vernon. Those discussions clarified the boundaries and property rights of the two states.
The tradeoffs to reach agreement were based on the shape of the bay and the colonial boundaries. Virginia, as it interpreted the language in its three charters, "owned" the mouth of the Chesapeake Bay. While Maryland might control the Potomac River, Virginia controlled the entrance to the Chesapeake Bay and all ocean-going traffic passing between Cape Charles and Cape Henry on the way to the Potomac River. Under the Articles of Confederation, Virginia could impose a high tax on all vessels sailing into the bay. Maryland's ports were on the bay and the rivers draining into the bay, not on the Atlantic coast - so nearly all commercial traffic going to (or from) Maryland could be forced to pay an import or export fee on their cargoes to Virginia.
Maryland and Virginia agreed in the Compact of 1785 that neither state could interfere with the other's trade or fishing on the Potomac River. Virginia and Maryland also agreed to allow each other free access on the Chesapeake Bay and Potomac River. The first provision in the Compact of 1785 stated:4
Through that statement, Virginia traded away its theoretical ability to impose tolls on Maryland vessels entering the Chesapeake Bay between Cape Charles and Cape Henry, near Norfolk. In exchange, Virginia was guaranteed free access to the Potomac River, where all the navigable portion of the river was claimed by Maryland.
The commissioners reached agreement for resolving conflict between two states, and also recognized that the current form of a confederated national government was not successful in dealing with other multi-state concerns. After resolving the Virginia/Maryland issues in the Compact of 1785, the commissioners called for another meeting among all the states to address larger interstate commerce issues. This led to the Annapolis Convention, which begat the Constitutional Convention in Philadelphia in 1787, which begat the current United States of America.
A new Constitution adopted replaced the Articles of Confederation in 1788. Under the Commerce Clause (authorizing the Federal Government to "regulate commerce with foreign nations, and among the several states, and with the Indian tribes"), individual states lost the authority to tax imports (and all export taxes were banned). Virginia could no longer impose a fee on ships sailing into the Chesapeake Bay to reach Maryland destinations, and Maryland could no longer tax vessels in the Potomac River headed to Virginia destinations.
Why did Virginia and Maryland settle their differences and agree to the Compact of 1785, when the rules would be changed only three years later with a new form of national government after the Constitution was ratified in 1788?
In 1785 it was not clear the 13 new states would remain under one federal government. The development of the Constitution was not pre-ordained; the leaders of the newly-independent states had no crystal ball showing that a Commerce Clause would change the authorities of the individual states. (To get a sense of the challenge faced by the negotiators trying to resolve a relatively minor conflict over the rights to the Potomac River, look at today's debates over the relative authority of individual states in the European Union.)
In 1829, a canal was opened to connect the northern tip of the Chesapeake Bay to the Delaware Bay. The Chesapeake and Delaware Canal bypassed the passage of Baltimore-bound shipping through Virginia, via the natural opening at Cape Charles/Cape Henry, and now carries 40% of all the shipping to the port of Baltimore.6 Had the Chesapeake and Delaware Canal been built before the Compact of 1785, ships would have been able to sail between Baltimore and the Atlantic Ocean without having to use the mouth of the Chesapeake Bay and sail through Virginia waters. Without the leverage of control over traffic in the lower Chesapeake Bay, who knows how the Maryland/Virginia negotiations over the boundary may have evolved...
In 1940, Congress gave its consent to a new interstate compact for managing the Potomac River. Maryland, West Virginia, Pennsylvania, Virginia, and the District of Columbia entered into a Congressionally-approved compact that created the Interstate Commission on the Potomac River Basin (ICPRB) and the Potomac Valley Conservancy District, to address water quality and related land resources issues in the Potomac River watershed.
In the 1950's, the dispute between Maryland and Virginia over rights to oysters and other resources in the Chesapeake Bay/Potomac River turned violent. Both states armed patrol vessels and the "Oyster Wars" led to a effort to abrogate the Compact of 1785. Virginia started a lawsuit at the Supreme Court (VIRGINIA v. MARYLAND, 355 U.S. 269), but state officials were able to negotiate their differences and replaced the Compact of 1785 with the Compact of 1958.
The 1958 agreement established the Potomac River Fisheries Commission, defined the jurisdictional boundaries for that commission's powers (in great detail for the Maryland side of the Potomac River, but simply referencing the mean low waterline of the Potomac River on the Virginia side, as marked by the Matthews-Nelson Survey of 1927). After both the Virginia and Maryland legislatures and the Maryland voters approved the 1958 agreement, Congress affirmed it in 1962.
The western extension of the boundary between Maryland and Virginia followed the Potomac River up to its "headspring," which was defined by the resolution of the Fairfax Grant boundaries to be at the starting point of the North Branch of the Potomac River. West of that point, the boundary was shaped by the Mason-Dixon Line.
Maryland and Pennsylvania got in a dispute about their colonial boundary based on problems with the royal grants to William Penn and Lord Calvert. Local surveyors had business relationships with colonial officials that could have affected their judgement, and the colonies wanted top-quality independent surveyors to demarcate the boundary. Two respected surveyors named Mason and Dixon were imported from England, and they surveyed the southern border of Pennsylvania in 1763.
Mason and Dixon's work impacted both Maryland's and Virginia's northern boundary. At that time, Virginia included what is today West Virginia, so the southern border of Pennsylvania west of the Fairfax Stone was the northern border of Virginia. The Englishmen did not survey all the way to the southwestern corner of Pennsylvania (near Pittsburgh), but the modern West Virginia/Pennsylvania boundary is a western extension of the actual line surveyed by Mason and Dixon.
In 1788, Francis Deakins surveyed land in western Maryland for compensating soldiers who fought in the Revolutionary War. He based his survey on the Fairfax Stone, using it to define the western boundary of the state. However, in 1850 Maryland claimed that the western edge of the colonial grant to Virginia was the South Branch of the Potomac River, not the North Branch. In 1897, Maryland even set a Potomac Stone at the headwaters of the South Branch as a rival for the Fairfax Stone at the headwaters of the North Branch.
The South Branch stream discharges more water than the North Branch, but in 1746 the surveyors of the Fairfax Grant chose the North Branch (with its wider valley) as the source of the Potomac River. Charles J. Faulkner, appointed by Governor Floyd, produced the initial defense of the Virginia claim in 1852, but it took until a Supreme Court decision in 1910 to resolve the dispute between the states completely. By that time, the dispute was between West Virginia (created in 1863) and Maryland.
On May 31, 1910, the Supreme Court established that the low-water mark of the south bank of the Potomac River was the Maryland-West Virginia boundary, applying the logic of the 1877 arbitration agreement (the Black-Jenkins Award) between Virginia-Maryland to West Virginia. Splitting Virginia into two separate states in 1863 did not change the court's opinion of the boundary upstream from the mouth of the Shenandoah River to the Fairfax Stone.
The Supreme Court also ruled that the West Virginia-Maryland boundary would begin about 1 mile north of the Fairfax Stone, where the Deakins Line crossed the North Branch. As a result, the Fairfax Stone itself is completrely within West Virginia, and is no longer on the border with Maryland.7
While all of Maryland was once part of Virginia, the Virginians fought (physically, with guns, resulting in deaths...) for only two parts: Kent Island and the Chespeake Bay.
In 1631, William Claiborne had established a trading post in the upper Chesapeake Bay on Kent Island, which is now crossed by the Chesapeake Bay Bridge (Route 50) between Annapolis and the Eastern Shore. The 1632 grant to Cecil Calvert abolished Claiborne's claim to the island, and blocked his efforts to compete with the Diutch and Swedes in New Amsterdam (New York) and Delaware for the fur trade with the Susquahannocks and other tribes.
Claiborne, who was an official in the government of the Virginia colony, objected to the shift from Virginia to Maryland and appealed to English officials in London. While those officials debated the issue, supporters of Claiborne and Maryland officials fought a minor civil war in the Chesapeake Bay, after Marylanders seized one of Claiborne's trading vessels in the bay.
Much to the disgust of the Virginia gentry, the colonial Virginia governor obeyed instructions from London to support the king's creation of the new colony of Maryland. Partially in response, the Virgnia gentry "thrust out" Governor Harvey and forced him to sail home to England in 1635, helping to establish the power of the locally-elected House of Burgesses vs. officials appointed by the king.
Maryland established complete control over Kent Island in 1637, after Claiborne's creditors decided to support Maryland. In 1644, however, Claiborne re-seized his old fur trading post during an anti-Catholic uprising that was triggered by Virginians. The Calverts regained control, but Claiborne once again stimulated another brief revolt in 1654 during the English Civil War. Once more the Calvert's were reinstated as the leaders of the Maryland colony, when the Puritan government in England sided with the Catholic family and ordered their proprietary powers restored in the colony.
According to the 1632 charter for Maryland, "the southern boundary of the grant was composed of two straight lines... a line from Watkin's Point East to the Sea, and a line from the southern point of the mouth of the Potomac to Watkin's Point. The location of these lines depended simply upon the position of these two points."8
The 1632 charter defined the southern point of the mouth of the Potomac as "a certain Place, called Cinquack, situate near the mouth of the said River." Cinquack was an Algonquian town identified by John Smith on his map of Virginia. Though the town was located several miles south of the mouth of the Potomac River, Maryland accepted that its boundary started at Smith Point (at the lighthouse, after it was constructed) and never tried to claim territory south to the old location of Cinquack.
However, the Maryland-Virginia boundary on the eastern side of the Chesapeake Bay and on the Eastern Shore was not clear. The confusion became important after the area was settled by religious dissidents (primarily Quakers and Puritans) who had been expelled from Virginia in 1660. (After the Restoration of Charles II made clear that the Puritans had lost political control in England, Governor Berkeley "cleaned house" in Virginia.). The religious dissenters from Virginia who settled on the Eastern Shore of Maryland could avoid paying taxes to either colonial government if the boundary was not defined - and Edmund Scarborough, the Surveyor General of Virginia, was agressive in asserting Virginia's claims to land on the Eastern Shore above the 38th parallel.
In 1668 Phillip Calvert of Maryland (uncle of the governor at the time, Charles Calvert) and Edmund Scarborough agreed to set the boundary along the 38th parallel, where the Potomac River empties into the Chesapeake Bay. The survey starts where the 38th parallel crosses the Pocomoke River, not at the edge of the Chesapeake Bay. As a result of starting at the Pocomoke River (perhaps to avoid a difficult traverse through marshland seen as having minimial value), the colonial officials in 1688 altered the 1632 charter boundaries. Using the main channel of the Pocomoke River to mark the colonial boundary between the eastern edge of the Chesapeake Bay and the 38th parallel gave Maryland some extra land, north and west of the Pocomoke River.
The Calvert-Scarborough line was surveyed with magnetic compasses, without correcting for the deviation from true north. A compass doesn't point to the North Pole; it points to magnetic north - a location NEAR, but not at, the geographic pole. After the boundary was accepted, it was realized that the line was about 5 degrees off from a true east-west slant. The line "tilts" to the northeast on the map today rather than runs due east. As a result, about 15,000 extra acres east of the Pocomoke River ended up in Virginia.9
A stickier problem was where the state line crossed the Chesapeake Bay and its various islands. Watkins Point, on the western edge of the Eastern Shore (that is, on the Chesapeake Bay side, not on the Atlantic Ocean) had been named as the dividing line in the 1632 Maryland charter. The charter also referenced the river Wighco (or Wigloo), based on Johh Smith's 1624 map. However, Virginia claimed that the exact location of Watkins Point referenced in the original Maryland charter was unclear by the 1850's.
In the 1850's, the two states started to resolve the issue. At the request of Virginia and Maryland, in 1858 Lieutenant Michler of the United States Topographical Engineers mapped the shorelines of the Eastern Shore and Chesapeake Bay islands (plus the location of the Fairfax Stone at the headwaters of the Potomac River. Michler's survey mapped the area, but determining where to draw the boundary line was a political rather than a surveying decision.
Though the states agreed that the Wigloo (or Wighco) mentioned in the charter was the Pocomoke River, Virginians wanted to harvest oysters in all of Pocomoke Bay and argued that "Watkins Point" was actually the mpouth of the Annamessex River further north - despite all the historic maps showing that the southwestern tip of a Somerset County peninsula still called Watkins Point was the reference point in the charter.
The 1877 Black and Jenkins arbitration affirmed the locally-accepted boundaries on Smith's Island (one of the Russell Isles on John Smith's map) between Horse Hammock-Sassafrass Hammock. Through that 1877 arbitration and a series of later adjustments, odd twists and turns in the Maryland-Virginia boundary throughout the Chesapeake Bay granted rights for Virginians to harvest the valuable fish and oyster resources of "Smith's Island, all of Fox Island, the great oyster rock known as Muddy Marsh in Tangier Sound, and the valuable crabbing flats from Green Harbor Island to Robin Hood Bar in Pocomoke Sound."11
After the Civil War, Maryland and Virginia disagreed on how to manage the oysters in the Chesapeake Bay. Maryland did not allow dredging, but Virginia permitted boats to scrape the bottom of the bay and disrupt the natural habitat. "Pirates" were accused of harvesting illegally on either side of the border.
Both states supported their separate rules (and watermen) by establishing state navies on the Chesapeake Bay. In 1882-83, Virginia's governor personally led two expeditions to capture oyster pirates at the mouth of the Rappahannock River.
In Virginia, a Board of the Chesapeake kept the Tangier and Pocomoke schooners , plus the Chesapeake and Accomac steamers on the bay, theoretically to protect Virginia watermen from the equivalent forces from shoot-outs between Maryland and Virginia fishermen. The Fisheries Commission inherited the responsibility in 1897, and added two other steamers, the Commodore Maury and James River. The Fisheries Commissioin was renamed the Marine Resources Commission in 1968. 12
Disputes about which state could enforce varying rules about dredging oysters, etc., continued through the 1850's, until the adoption of another Maryland-Virginia Compact in 1958 (at Mount Vernon, again). That 1958 agreement superceded the arrangements made in the 1785 compact.
Virginia and Maryland keep debating the 1632 boundary dispute and how the Compact of 1785 limits Maryland's control over the bottom of the Potomac River. A 1958 Maryland-Virginia Compact replaced the Compact of 1785 in hopes of resolving disputed claims to oyster beds and fishery resources - but lawsuits continue to cite colonial-era documents, as well as the 1958 agreement.
In 1997, Maryland claimed that the Fairfax County Water Authority needed a Maryland state permit, in order to extend a water pipe to the middle of the Potomac River. Fairfax wanted to minimize the sediment in the water that it will treat at its Corbalis Water Treatment plant, near the Loudoun County line, by extracting raw water from the middle of the river. The old Fairfax County intake pipe on the southern shoreline was receiving water with too much sediment, partly due to muddy runoff from housing developments in Loudoun County. Fairfax wanted to suck cleaner water from the middle of the river. The water in the middle of the Potomac River is cleaner, in large part because C&O Canal National Historical Park on the Maryland side provides a buffer of natural vegetation and there is less mud flowing into the Potomac on the north bank.
That proposal created yet one more Virginia v. Maryland lawsuit in front of the US Supreme Court. Maryland opposed the plans of the Fairfax County Water Authority (now Fairfax Water), and tried to force the Virginia county to get a Maryland state permit before constructing the intake pipe on the bed of the Maryland river. Part of the "back story" is that Maryland wanted Virginia to reduce the impacts of shoreline development that pollute the Potomac River. Simply avoiding those impacts by extending the intake pipe addressed the sympton without dealing with the cause.
In 2003, the US Supreme Court ruled that Fairfax County has the right to place the intake pipe on Maryland's river bed without having to obtain a permit from Maryland. Maryland owns the whole river, due to the wording in the 1634 charter, but various bi-state negotiations and court decisions (especially the 1877 Black-Jenkins Award) have made it possible for Virginia to use the Potomac River.
NOTE: Virginia does not "own" any of the Potomac River below the low-water mark, but Maryland does not own all of the river either. The District of Columbia actually owns some of the Potomac River. A portion of the river between Jones Point and Chain Bridge was once part of Maryland, but was incorporated within the boundaries of the District of Columbia when it was established. Maryland's rights to the Potomac transferred at that time to the District, and the Boundary Channel near the Pentagon is owned by DC. (After West Virginia was established in 1863, Maryland retained its claims to the entire river, from Harpers Ferry up to the Fairfax Stone. West Virginia stops at the shoreline, and does not extend into the middle of the Potomac River.)
