Editing Mason–Dixon line

{{Short description|Surveyed border line between U.S. states of Delaware, Maryland, and Pennsylvania}}
{{Other uses|Mason Dixon (disambiguation){{!}}Mason Dixon}}
{{Use American English|date = August 2019}}
{{Use mdy dates|date=June 2013}}
[[File:Mason-dixon-line.gif|thumb|Map of the original Mason–Dixon line (in red)]]
[[File:Mason and Dixon.png|thumb|A 1910 illustration of [[Charles Mason]] and [[Jeremiah Dixon]] surveying the line]]
[[File:Mason Dixon Line - Rail Trail.jpg|thumb|The Mason–Dixon line, where the [[Torrey C. Brown Rail Trail]] becomes the [[York County Heritage Trail]] near [[New Freedom, Pennsylvania]]]]

The '''Mason–Dixon line''', sometimes referred to as '''Mason and Dixon's Line''', is a [[demarcation line]] separating four [[U.S. states]]: [[Pennsylvania]], [[Maryland]], [[Delaware]] and [[West Virginia]]. It was [[Surveying|surveyed]] between 1763 and 1767 by [[Charles Mason]] and [[Jeremiah Dixon]] as part of the resolution of a border dispute involving Maryland, Pennsylvania, and Delaware in the [[colonial United States]].<ref>{{cite book|url=https://books.google.com/books?id=0_T5AgAAQBAJ|title=Boundaries: How the Mason-Dixon Line Settled a Family Feud and Divided a Nation|author=Sally M. Walker|year=2014|publisher=Candlewick Press|isbn=978-0763670368}}</ref> 

The largest portion of the Mason–Dixon line, along the southern Pennsylvania border, later became informally known as the boundary between the [[Slave states and free states|Southern slave states and Northern free states]]. This usage came to prominence during the debate around the [[Missouri Compromise]] of 1820, when drawing boundaries between slave and free territory,<ref>"The Missouri Compromise of 1820 designated Mason and Dixon’s west line as the national divide between the 'free' and 'slave' states east of the Ohio River, and the line suddenly acquired new significance." {{cite web|first=John|last=Mackenzie|url=http://www1.udel.edu/johnmack/mason_dixon/|title=A brief history of the Mason–Dixon Line|archive-url=https://web.archive.org/web/20180717185851/http://www1.udel.edu/johnmack/mason_dixon/ |archive-date=July 17, 2018|website=APEC/CANR, University of Delaware|access-date=2017-01-05}}</ref> and resurfaced during the [[American Civil War]], with [[border states (American Civil War)|border states]] also coming into play. The [[Confederate States of America]] claimed the [[Virginia]] (now West Virginia) portion of the line as part of its northern border, although it never exercised meaningful control that far north{{snd}}especially after West Virginia separated from Virginia and joined the [[Union (American Civil War)|Union]] as a separate state in 1863. It is still used today in the figurative sense of a line that separates the [[Northeastern United States|Northeast]] and [[Southern United States|South]] culturally, politically, and socially {{Xref|text=(see [[Dixie]])}}.

==Background==
{{main|Penn–Calvert boundary dispute}}
[[File:Mason-Dixon Survey Historical Marker Front and South Sts Philadelphia PA (DSC 3153).jpg|thumb|A historical marker at [[Front Street (Philadelphia)|Front]] and [[South Street (Philadelphia)|South]] streets in [[Philadelphia]], where the survey began]]
[[History of Maryland#Colonial Maryland|Maryland's charter]] of 1632 granted [[Cecil Calvert, 2nd Baron Baltimore|Cecil Calvert]] land north of the entire length of the [[Potomac River]] up to the [[40th parallel north|40th parallel]].<ref name="msa">{{cite web|url=http://msa.maryland.gov/megafile/msa/speccol/sc6000/sc6046/000000/000001/000000/000007/pdf/msa_sc6046_1_7.pdf |title=Maryland Geological Survey, Volume 7 |publisher=Maryland State Archives |access-date=2015-03-20}} See section "History of the Boundary Dispute Between the Baltimores and Penns Resulting in the Original Mason and Dixon Line" by Edward Bennett Matthews</ref> A problem arose when [[Charles II of England|Charles II]] granted a [[History of Pennsylvania#Province_of_Pennsylvania|charter for Pennsylvania]] in 1681. The grant defined Pennsylvania's southern border as identical to Maryland's northern border, but described it differently, as Charles relied on an inaccurate map. The terms of the grant clearly indicate that Charles II and [[William Penn]] believed the 40th parallel would intersect the [[Twelve-Mile Circle]] around [[New Castle, Delaware]], when in fact it falls north of the original boundaries of the City of [[Philadelphia]], the site of which [[William Penn|Penn]] had already selected for his colony's capital city. Negotiations ensued after the problem was discovered in 1681. A compromise proposed by Charles II in 1682, which might have resolved the issue, was undermined by Penn receiving the additional grant of the "Three Lower Counties" along [[Delaware Bay]], which later became the [[Delaware Colony]], a satellite of Pennsylvania. Maryland considered these lands part of its original grant.<ref name=hubbard>{{cite book |last= Hubbard | first= Bill Jr. |title= American Boundaries: the Nation, the States, the Rectangular Survey |year= 2009 |publisher= University of Chicago Press |isbn= 978-0226355917 |pages= 20–29}}</ref>

The conflict became more of an issue when settlement extended into the interior of the colonies. In 1732, the [[Proprietary Governor]] of Maryland, [[Charles Calvert, 5th Baron Baltimore]], signed a provisional agreement with [[William Penn]]'s sons, which drew a line somewhere in between and renounced the Calvert claim to Delaware. But later, Lord Baltimore claimed that the document he had signed did not contain the terms he had agreed to, and refused to put the agreement into effect. Beginning in the mid-1730s, violence erupted between settlers claiming various loyalties to Maryland and Pennsylvania. The border conflict would be known as [[Cresap's War]].<ref name=expansion>{{cite journal|url=https://journals.psu.edu/phj/article/view/24559/24328|author=Paul Doutrich|title=Cresap's War: Expansion and Conflict in the Susquehanna Valley|journal=Pennsylvania History|volume=53|date=1986|pages=89–104|publisher=Cip.cornell.edu}}</ref>

Progress was made after a [[Court of Chancery]] ruling affirming the 1732 agreement, but the issue remained unresolved until [[Frederick Calvert, 6th Baron Baltimore]] ceased contesting the claims on the Maryland side and accepted the earlier agreements. Maryland's border with Delaware was to be based on the [[Transpeninsular Line]] and the Twelve-Mile Circle around New Castle. The Pennsylvania–Maryland border was defined as the line of latitude {{convert|15 |miles}} south of the southernmost house in Philadelphia (on what is today [[South Street (Philadelphia)|South Street]]). As part of the settlement, the Penns and Calverts commissioned the English team of [[Charles Mason]] and [[Jeremiah Dixon]] to [[surveying|survey]] the newly established boundaries between the [[Province of Pennsylvania]], the [[Province of Maryland]], and [[Delaware Colony]].<ref name=hubbard/>

In 1779, Pennsylvania and Virginia agreed "To extend Mason's and Dixon's line, due west, five degrees of longitude, to be computed from the river Delaware, for the southern boundary of Pennsylvania, and that a meridian, drawn from the western extremity thereof to the northern limit of the said state, be the western boundary of Pennsylvania for ever."<ref>{{cite book |last=Barton |first=William |title= Memoirs of the life of David Rittenhouse, LLD. F.R.S. |year=1818 |publisher=E. Parker |pages=282–283 |isbn=978-0608436135 |url= https://books.google.com/books?id=_J8RAAAAYAAJ&pg=PA283}}</ref>

After Pennsylvania abolished [[Slavery in the United States|slavery]] in 1781, the east–west part of this line and the [[Ohio River]] became a border between [[slave and free states]],<ref>{{cite web |last=Hudson |first=J. Blaine |title=Crossing the "Dark Line": Fugitive Slaves and the Underground Railroad in Louisville and North Central Kentucky (excerpt) |url=http://www.ket.org/underground/research/crossing.htm |work=KET's Underground Railroad: Passage to Freedom, with Kentucky Humanities Association |access-date=February 25, 2007 |archive-url=https://web.archive.org/web/20130212015127/http://www.ket.org/underground/research/crossing.htm |archive-date=February 12, 2013 |url-status=dead}}</ref> with Delaware<ref>{{cite web |title= Slavery in Delaware |url= http://slavenorth.com/delaware.htm |website= Slavery in the North |access-date=6 October 2015 }}</ref> retaining slavery until the [[Thirteenth Amendment to the United States Constitution|13th Amendment]] was ratified in 1865.

==Geography of the line==
[[File:Delaware-wedge.svg|thumb|Diagram of the survey lines creating the Mason–Dixon line and [[Wedge (border)|The Wedge]]]]
[[File:Marycolony.png|thumb|The [[Province of Maryland]], 1632–1776]]
Mason and Dixon's actual survey line began to the south of [[Philadelphia]], and extended from a [[Benchmark (surveying)|benchmark]] east to the [[Delaware River]] and west to what was then the boundary with western Virginia.

The surveyors also fixed the boundary between [[Delaware]] and [[Pennsylvania]] and the approximately north–south portion of the boundary between Delaware and [[Maryland]]. Most of the Delaware–Pennsylvania boundary is an [[Twelve-Mile Circle|arc]], and the Delaware–Maryland boundary does not run truly north–south because it was intended to bisect the [[Delmarva Peninsula]] rather than follow a meridian.<ref>{{cite book |title=Drawing the Line How Mason and Dixon Surveyed the Most Famous Border in America |publisher=John Wiley |author=Danson, Edwin |year=2001 |pages=54}}</ref>

Mason and Dixon also confirmed the earlier survey delineating Delaware's southern boundary from the Atlantic Ocean to the "Middle Point" stone (along what is today known as the ''Transpeninsular Line''). They proceeded nearly due north from this to the Pennsylvania border.{{citation needed|date=October 2020}}

The Maryland–Pennsylvania boundary is an east–west line with an approximate mean [[latitude]] of 39°43′20″&nbsp;N ([[datum (geodesy)|Datum]] [[WGS&nbsp;84]]). In reality, the east-west Mason–Dixon line is not a true straight line in the geometric sense, but is instead a [[polygonal chain]], a series of many adjoining line segments, following a path between latitude 39°43′15″&nbsp;N and 39°43′23″&nbsp;N.

The surveyors also extended the boundary line {{convert|40 |miles}} west of Maryland's western boundary, into territory that was still in dispute between Pennsylvania and Virginia, though this was contrary to their original charter.<ref name=hubbard/> Mason and Dixon's survey was finished on October&nbsp;19, 1767, about {{convert|31 |miles}} east of what is now Pennsylvania's southwest corner. Where the surveyors finished their survey became known as the [[Mason and Dixon Survey Terminal Point]]<ref name="Wilford2001">{{cite book |last= Wilford |first= John Noble |title=The Mapmakers: Revised Edition |url= https://books.google.com/books?id=vHy44e1nRXcC&pg=PA215 |access-date= 2012-11-01 |year=2001 |publisher= Random House Digital, Inc. |isbn=978-0375708503 |pages=215–216}}</ref>

In 1774, commissioners from Pennsylvania and Virginia met to negotiate their boundary, which at the time involved Pennsylvania's southern border west of Maryland and its entire western border. Both sides agreed that Pennsylvania's grant made its western border a tracing of the course of the Delaware River, displaced five degrees (approximately 265 miles) to the west. And both sides thought this would place [[Fort Pitt (Pennsylvania)|Fort Pitt]] in Virginia territory (in fact it would not have). With that in mind, the governor of Pennsylvania argued that, despite the agreement reached with Maryland, Pennsylvania's southern border west of Maryland was still the [[39th parallel north|39th parallel]], about {{convert|50 |miles}} south of the Mason–Dixon line. Negotiations continued for five years, with a series of proposed lines. In the end, a compromise was reached: the Mason–Dixon line would be extended west to a point five degrees west of the Delaware River. To compensate Pennsylvania for the claimed territory lost, its western boundary would be run due north rather than copying the course of the Delaware River.<ref name=hubbard/>

The Mason–Dixon line was [[Milestone|marked by stones every mile]] {{convert|1|miles}} and "crownstones" every {{convert|5|miles}}, using stone shipped from England. The Maryland side says "(M)" and the Delaware and Pennsylvania sides say "(P)".<ref>{{Cite web |last=Ecenbarger |first=William |date=2021-06-24 |title=Stolen, vandalized, buried, lost: Mason-Dixon Line markers are getting surveyed to be saved |url=https://www.inquirer.com/news/mason-dixon-line-pennsylvania-philadelphia-maryland-survey-historic-register-20210624.html |url-status=live |archive-url=https://web.archive.org/web/20210624224749/https://www.inquirer.com/news/mason-dixon-line-pennsylvania-philadelphia-maryland-survey-historic-register-20210624.html |archive-date=2021-06-24 |access-date=2022-02-15 |website=[[The Philadelphia Inquirer]] |language=en}}</ref>
Crownstones included both coats of arms.

Many of the original stones are still visible, resting on public land and protected by iron cages; a number have gone missing or were buried.<ref name = "WaPo">{{cite news|first=William|last=Ecenbarger|title=Neglecting the Mason–Dixon boundary stones|newspaper=The Washington Post|date=January 1, 2017|page=C4}}</ref>

The actual locations of the stones may differ a few hundred feet east or west from the exact positions where Mason and Dixon intended to place them, still, the line drawn from stone to stone forms the legal boundary.{{citation needed |date=October 2020}}

The lines have been resurveyed several times over the centuries without substantive changes to Mason's and Dixon's work, and additional [[Benchmark (surveying)|benchmarks]] and [[survey marker]]s were placed where necessary.

==History==
[[File:Masondixonmarker.jpg|thumb|A crownstone boundary monument on the Mason–Dixon line; these markers were originally placed at every 5th mile ({{cvt|5|mi |disp=out}}) along the line, ornamented with family coats of arms facing the state they represented. The coat of arms of Maryland's founding [[Cecilius Calvert, 2nd Baron Baltimore|Calvert]] family is shown; on the other side, are the arms of [[William Penn]], who founded the [[Province of Pennsylvania]]]]
[[File:A Plan of the West Line or Parallel of Latitude - WDL.png|thumb|"A Plan of the West Line or Parallel of Latitude" by Charles Mason, published in 1768]]
[[File:The great allegheny passage in fall view of wind turbines.jpg|thumb|The [[Mason-Dixon Trail]]]]
The line was established to end a [[Cresap's War|boundary dispute]] between the [[British colonization of the Americas|British colonies]] of Maryland and Pennsylvania/Delaware. Maryland had been granted the territory north of the [[Potomac River]] up to the 40th parallel. Pennsylvania's grant defined the colony's southern boundary as following a [[Twelve-Mile Circle|12-mile (radius) circle]] ({{cvt|12|mi |disp=out}}) counter-clockwise from the Delaware River until it hit "the beginning of the fortieth degree of Northern latitude." From there the boundary was to follow the 40th parallel due west for five degrees of longitude. But the 40th parallel does not, in fact, intersect the 12-mile circle, instead lying significantly farther north. Thus Pennsylvania's southern boundary as defined in its charter was contradictory and unclear. The most serious problem was that the Maryland claim would put [[Philadelphia]], the largest city in Pennsylvania, in Maryland.<ref name=hubbard/>

The dispute was peacefully resolved in 1767<ref>{{cite book|last=Konkle|first=Burton Alva|year=1932|title=Benjamin Chew 1722–1810: Head of the Pennsylvania judiciary system under colony and commonwealth|location=Philadelphia|publisher=University of Pennsylvania Press|pages=63–64|jstor=j.ctv5132d8.17}}</ref> when the boundary was fixed as follows:
* Between Pennsylvania and Maryland:
** The parallel (latitude line) {{convert|15|mi|km|0}} south of the then southernmost point in Philadelphia, measured to be at about 39°43′ N and agreed upon as the Maryland–Pennsylvania line.
* Between Delaware and Maryland:
** The existing east–west transpeninsular line from the [[Atlantic Ocean]] to the [[Chesapeake Bay]], as far as its midpoint from the Atlantic.
** A [[Twelve-Mile Circle|12-mile (radius) circle]] ({{convert|12|mi|km|0|abbr=on}}) around the city of New Castle, Delaware.
** A "tangent line" connecting the midpoint of the transpeninsular line to the western side of the 12-mile circle.
** A "north line" along the meridian (line of longitude) from the tangent point to the Maryland-Pennsylvania border.
** Should any land within the 12-mile circle fall west of the north line, it would remain part of Delaware. (This was indeed the case, and this border is the "arc line".)

The disputants engaged an expert British team, astronomer [[Charles Mason]] and surveyor [[Jeremiah Dixon]], to survey what became known as the Mason–Dixon line.<ref name="WDL">{{cite web |url = http://www.wdl.org/en/item/9573/ |title = A Plan of the West Line or Parallel of Latitude |website = [[World Digital Library]] |year = 1768 |access-date = 2013-06-30 }}</ref><ref>{{cite news |title=The men who drew the Mason–Dixon Line |url = https://www.bbc.co.uk/news/uk-england-40638673 |access-date = 2 September 2017 |work=BBC |date=2 September 2017 }}</ref> It cost the Calverts of Maryland and the Penns of Pennsylvania £3,512 [[shilling|9/]] [[Penny (British pre-decimal coin)|–]] ({{Inflation|UK|3512.45|1767|fmt=eq|cursign=£|r=0}}) to have {{convert|244|mi|km|0}} surveyed with such accuracy. To them the money was well spent, for in a new country there was no other way of establishing ownership.<ref>{{Cite book
   |last=Linklater
   |first=Andro
   |title=Measuring America
   |publisher=Penguin
   |date=2003
   |page=[https://archive.org/details/isbn_9780452284593/page/33 33]
   |isbn=978-0452284593
   |url=https://archive.org/details/isbn_9780452284593/page/33
   }}</ref><ref>{{Cite journal
   |url= http://www.americanheritage.com/articles/magazine/ah/1964/2/1964_2_22.shtml
   |title= Mason & Dixon: their Line and its Legend
   |last1= Mason
   |first1= A. Hughlett
   |last2= Swindler
   |first2= William F.
   |journal= American Heritage
   |date= February 1964
   |volume= 15
   |issue= 2
   |access-date= 2008-11-08
   |archive-date= December 5, 2008
   |archive-url= https://web.archive.org/web/20081205010941/http://americanheritage.com/articles/magazine/ah/1964/2/1964_2_22.shtml
   |url-status= dead
   }}</ref>
The [[Mason-Dixon Trail]] stretches on or near Pennsylvania's border with Delaware and Maryland and is a popular attraction to tourists.

The Mason–Dixon line is made up of four segments corresponding to the terms of the settlement:
* the tangent line
* the north line
* the arc line
* the 39°43′ N parallel

The most difficult task was fixing the tangent line, as they had to confirm the accuracy of the transpeninsular line midpoint and the 12-mile circle, determine the tangent point along the circle, and then actually survey and monument the border. They then surveyed the north and arc lines. They did this work between 1763 and 1767. This actually left a small [[Wedge (border)|wedge of land]] in dispute between Delaware and Pennsylvania until 1921.<ref>{{cite journal | title = Annual Report of the Director | journal = U.S. Coast and Geodetic Survey | year = 1895 | page = 195 | url = https://books.google.com/books?id=JgEPAQAAIAAJ | access-date = 2012-12-20 | author = U.S. Coast And Geodetic Survey }}</ref>{{better source needed|date=December 2012}}

In April 1765, Mason and Dixon began their survey of the more famous Maryland–Pennsylvania line. They were commissioned to run it for a distance of five degrees of longitude west from the Delaware River, fixing the western boundary of Pennsylvania (see the entry for [[Yohogania County]]). However, in October 1767, at [[Dunkard Creek]] near [[Mount Morris, Pennsylvania]], nearly {{convert|244|mi|km|0}} west of the Delaware, their [[Iroquois]] guides refused to go any further, having reached the border of their lands with the [[Lenape]], with whom they were engaged in hostilities. As a result, the group was forced to quit, and on October 11, they [[Mason and Dixon Survey Terminal Point|made their final observations]], {{convert|233|mi|km}} from their starting point.<ref>{{cite book | title= Drawing the Line: How Mason and Dixon Surveyed the Most Famous Border in America |first= Edwin |last=Danson |publisher= John Wiley and Sons |year=2001 |pages=178–179 |url = https://books.google.com/books?id=dLDLuQ-xn34C&pg=PA178 |isbn = 978-0471437048 }}</ref>

In 1784, surveyors [[David Rittenhouse]] and [[Andrew Ellicott]] and their crew completed the survey of the Mason–Dixon line to the southwest corner of Pennsylvania, five degrees from the Delaware River.{{NoteTag|Four surveyors were appointed by each of the states: Virginia appointed [[James Madison (bishop)|Dr. James Madison]], Robert Andrews, [[John Page (Virginia politician)|John Page]], and [[Andrew Ellicott]], Pennsylvania appointed Dr. John Ewing (provost of University of Penn.), [[John Lukens]] (surveyor general of Penn.), [[Thomas Hutchins]], and [[David Rittenhouse]]. Andrews and Ellicott completed the west end of the line for Virginia,<ref>{{cite book |last = Mathews |first = Catherine [[Van Cortlandt family|Van Courtlandt]] |title = Andrew Ellicott, His Life and Letters |url = https://books.google.com/books?id=rpMNAAAAYAAJ&pg=PA17 |year=1908 |publisher=The Grafton Press |location=New York |pages=17–19 |isbn = 978-0795015106 }}</ref> while Hutchins and Ewing did so for Pennsylvania.<ref>{{cite book |last=Hicks |first=Fredrick |editor-first=Fredrick |editor-last=Hicks |title=A Topographical Description of Virginia, Pennsylvania, Maryland and North Carolina, reprinted from the original edition of 1778 |url = https://books.google.com/books?id=irTRAAAAMAAJ |year=1904 |publisher=The Burrow Brothers Company |location=Cleveland |page=32 |chapter=Biographical Sketch of Thomas Hutchins}}</ref>}} Other surveyors continued west to the Ohio River. The section of the line between the southwestern corner of Pennsylvania and the river is the county line between [[Marshall County, West Virginia|Marshall]] and [[Wetzel County, West Virginia|Wetzel]] counties, West Virginia.<ref>{{cite web |url = http://philadelphiaencyclopedia.org/archive/mason-dixon-line/ |title = Mason–Dixon Line |date = 2014 |access-date = 2019-10-26 |website = The Encyclopedia of Greater Philadelphia |publisher = Rutgers University |last = Strang |first = Cameron }}</ref>

As the 20th century moved along and modern roadways came to northeastern Maryland and Delaware, the old boundary line was noted by construction crews, newspaper columnists, and the traveling public. When contractors started working on a section of Route 40, a modern dual highway between Elkton and Glasgow, they discovered a time and weather battered original Mason Dixon Marker. It was relocated to northside of the highway and when the governors of Delaware and Maryland dedicated the highway on June 26, 1941, newspaper reporters took note of the ancient old relic.<ref name="A Fallen Mason Dixon Monument">{{Cite web |date=2019-12-22 |title=A Fallen Mason Dixon Monument |url=https://cecilcountyhistory.com/mason-dixon-monument/ |access-date=2022-05-01 |website=Window on Cecil County's Past |language=en-US}}</ref>

Although greatly mangled by traffic in the second half of the twentieth century, it still stands today. But long before bulldozers and other heavy equipment started moving earth for the dual highway before World War II, there were concerns about the preservation of this monument. In 1885, the Cecil Democrat reported that after 119-years, the stone on the road from Elkton to Glasgow had "yielded to the action of the elements and fell over." The editor urged the Cecil County Commissioners, Commissioner of the Land Office, Governor or some public minded citizen to preserve this "old time-honored, moss-covered relic of a generation, which has passed away. . . "<ref name="A Fallen Mason Dixon Monument"/>

On November 14, 1963, during the bicentennial of the Mason–Dixon line, U.S. President [[John F. Kennedy]] opened a newly completed section of [[Interstate 95]] where it crossed the Maryland–Delaware border. After the president, flanked by the governors of Delaware and Maryland, cut a ribbon opening the Interstate, they moved to the grassy median strip where a replica Mason and Dixon Marker had been placed for the bicentennial. There President Kennedy and the governors unveiled a limestone replica.<ref>{{Cite web |date=2018-11-17 |title=President Kennedy Unveiled Mason Dixon Marker |url=https://cecilcountyhistory.com/president-kennedy-at-the-mason-dixon-line/ |access-date=2022-05-01 |website=Window on Cecil County's Past |language=en-US}}</ref> It was one of his last public appearances before his [[John F. Kennedy assassination|assassination]] in [[Dallas, Texas]]. The [[Delaware Turnpike]] and the [[John F. Kennedy Memorial Highway (Maryland)|Maryland portion]] of the new road were later designated as the John F. Kennedy Memorial Highway.

The Mason–Dixon line has been resurveyed three times: in 1849, 1900, and in the 1960s.<ref name="WDL" />

In 2020, 30 volunteers, at the behest of the [[Maryland Department of Natural Resources|Maryland Geological Survey]], started a project to locate and document the 226 remaining Mason-Dixon Line stones, which were placed every mile in the 18th century to mark the border between Pennsylvania and Maryland. The stones are historically significant because they represent one of the first [[Geodesy|geodetic]] surveys ever conducted in North America. The volunteers hope to get the stones listed on the National Register of Historic Places, which will help to preserve them for future generations. By 2023, the volunteers found 218 of the often-hidden 500-pound limestone stone markers quarried in England.<ref>{{cite news |last=Simpson |first=Ashley |url=https://www.popularmechanics.com/science/archaeology/a45836176/mason-dixon-line-volunteers/ |title=Volunteers are Racing to Save the Crumbling Mason-Dixon Line |work=[[Popular Mechanics]] |date=2024-01-02 |accessdate=2024-01-03 }}</ref>

==Systematic errors and experiments to weigh the Earth==
Mason and Dixon achieved a high level of accuracy in the survey due to the work of [[Nevil Maskelyne]], some of whose instruments they used.<ref name="davies">{{Cite journal|last=Davies|first=R.D|title=A Commemoration of Maskelyne at Schiehallion|journal=[[Quarterly Journal of the Royal Astronomical Society]]|volume=26|issue=3|pages=289–294|bibcode=1985QJRAS..26..289D|year=1985}}</ref> There was keen interest in their work and much communication between the surveyors, Maskelyne and other members of the British Scientific establishment in the [[Royal Society]] in Britain, notably [[Henry Cavendish]].<ref name="journal">Note the comments on Cavendish's speculation in the introductory notes, and the multiple correspondences with Maskelyne in: {{Cite web|last=Mason|first=Charles|author-link=Charles Mason|author2=Dixon, Jeremiah|author-link2=Jeremiah Dixon|title=The Journal of Charles Mason and Jeremiah Dixon 1763–1768|url=http://www.mdlpp.org/pdf/library/JournalofMasonandDixon.pdf|access-date=2011-01-05|archive-date=December 30, 2017|archive-url=https://web.archive.org/web/20171230025832/http://www.mdlpp.org/pdf/library/JournalofMasonandDixon.pdf|url-status=dead}}</ref><ref name="maskelyne_fellowship">[[Nevil Maskelyne]] was elected a [[List of Fellows of the Royal Society|Royal Society Fellow]] on April 27, 1758; see {{Cite web|url=http://royalsociety.org/WorkArea/DownloadAsset.aspx?id=4294972811|format=pdf|publisher=[[Royal Society]]|title=List of Fellows of the Royal Society 1660–2007|volume=K–Z|page=238|year=2007|access-date=2011-01-05|url-status=dead|archive-url=https://web.archive.org/web/20101130205428/http://royalsociety.org/WorkArea/DownloadAsset.aspx?id=4294972811|archive-date=November 30, 2010}}</ref><ref name="cavendish_fellowship">[[Henry Cavendish]] was elected a [[List of Fellows of the Royal Society|Royal Society Fellow]] on May 1, 1760; see {{Cite web|url=http://royalsociety.org/WorkArea/DownloadAsset.aspx?id=4294972811|format=pdf|publisher=[[Royal Society]]|title=List of Fellows of the Royal Society 1660–2007|volume=A–J|page=66|year=2007|access-date=2011-01-05|url-status=dead|archive-url=https://web.archive.org/web/20101130205428/http://royalsociety.org/WorkArea/DownloadAsset.aspx?id=4294972811|archive-date=November 30, 2010}}</ref>

During such survey work, it is normal to survey from point to point along the line and then survey back to the starting point, where if there were no errors the origin and re-surveyed position would coincide.<ref name="natres">{{Cite web|title=Specifications and Recommendations for Control Surveys and Survey Markers|url=http://www.geod.nrcan.gc.ca/publications/specs/index_e.php#ExpectedAccuracy|publisher=[[Natural Resources Canada]]|page=Table E-VI Position Differences |quote=Double run in straight line by helicopter between control spaced at 80 km.|date=December 27, 2007|access-date=2011-01-06|archive-url=https://web.archive.org/web/20110526012704/http://www.geod.nrcan.gc.ca/publications/specs/index_e.php#ExpectedAccuracy|archive-date=May 26, 2011|url-status=dead}}</ref> Normally the return errors would be random{{snd}}i.e. the return survey errors compared to the intermediate points back to the start point would be spatially randomly distributed around the start point.<ref name="taylor">{{cite book|title=An Introduction to Error Analysis: The Study of Uncertainties in Physical Measurements|last=Taylor|first=John Robert|url=https://books.google.com/books?id=giFQcZub80oC&pg=PA94|page=94, §4.1 |isbn=093570275X|year=1999|publisher=University Science Books|access-date=2011-01-05}}</ref> Mason and Dixon found that there were larger than expected [[systematic error]]s, i.e. non-[[random error|random]] errors, that led the return survey consistently being in one direction away from the starting point.<ref name="mentzer">{{Cite web|url=https://caf783ab-f4aa-469d-a4ff-2c3a19268299.filesusr.com/ugd/6f029b_b08999b366b24ef79bdbeff2278b80e0.pdf|title=How Mason and Dixon Ran Their Line|last=Mentzer|first=Robert|access-date=2019-12-01}}</ref>

When this information got back to the Royal Society members, Henry Cavendish realised that this may have been due to the gravitational pull of the [[Allegheny Mountains]] deflecting the [[theodolite]] [[plumb-bob]]s and [[spirit level]]s toward them to the west.<ref name="schaffer">{{Cite interview|last=Schaffer|first=Simon|subject-link=Simon Schaffer|date=May 20, 2010 |work=[[BBC Radio 4]]|title=The Cavendish Family in Science}}</ref><ref name="tretkoff"/> Maskelyne then proposed measuring the gravitational force causing this deflection induced by the pull of a nearby mountain upon a plumb-bob in 1772 and sent Mason (who had returned to Britain) on a site survey through central England and Scotland to find a suitable location during the summer of 1773.<ref name="maskelyne">{{Cite journal
| last = Maskelyne
| first = Nevil
| author-link = Nevil Maskelyne
| title = An account of observations made on the mountain Schehallien for finding its attraction
| journal = [[Philosophical Transactions of the Royal Society of London]]
| location = London
| date = January 1, 1775
| volume = 65
| pages = 500–542
| doi = 10.1098/rstl.1775.0050
| quote = Accordingly Mr. [[Charles Mason]], who had been employed on several astronomical occasions by the [[Royal Society]], was appointed to make a tour through the Highlands of Scotland in the summer of the year 1773, taking notice of the principal hills in England which lay in his route either in his going or in his return.
| doi-access = free
}}</ref><ref name="sillitto">{{Cite web
| last = Sillitto
| first = Richard M.
| title = Maskelyne on Schiehallion
| url = http://www.sillittopages.co.uk/schie/schie90.html
| date = October 31, 1990
| quote = The Royal Society agreed to a proposal that it despatch a surveyor, a Mr [[Charles Mason]] whom they had previously employed on astronomical projects, all the way to Scotland and back, to survey likely-looking mountains, and to select a suitable mountain – ideally it should be a steep-sided cone, or a wedge with its apex ridge running W – E and with steep faces to N and S, and separated from the nearest neighbours to N and S by low land. Mr Mason selected for them a mountain at "the centre of Scotland", [[Schiehallion]] – a wedge, with the summit ridge running nearly W – E, 3547 ft above sea level at its western summit, about 3000 ft at the E-end of the ridge; it presents steep faces to the trench to the N which contains Loch Rannoch and Loch Tummel, and to the deep Gleann Mor to the S. [An approximate altitude for Gleann Mor is 1500 feet, and for the land at the same distance to the north of the ridge is 1600 ft.]
| location = [[The Royal Philosophical Society of Glasgow]]
| access-date = 2011-01-03
}}</ref><ref name="stanley">{{Cite book | last = Mackenzie | first = A. Stanley | year = 1900
| title = The Laws of Gravitation: Memoirs by Newton, Bouguer and Cavendish; together with abstracts of other important memoirs
| page = 53
| chapter = Account of Maskelyne's experiments on Schehallien
| location = New York
| publisher = American Book Company
| access-date = 2011-01-03
| chapter-url = https://books.google.com/books?id=O58mAAAAMAAJ&pg=PA59
| quote = In 1772...The proposal was favourably received by the [[Royal Society|Society]], and Mr. [[Charles Mason]] was sent to examine various hills in England and Scotland, and to select the most suitable (32). Mason found the two hills referred to by [[Nevil Maskelyne|Maskelyne]] were not suitable; and fixed upon [[Schiehallion|Schehallien]] in Perthshire as offering the best situation.}}</ref> Mason selected [[Schiehallion]] at which to conduct what became known as the [[Schiehallion experiment]], which was carried out primarily by Maskelyne and determined the density of the Scottish mountain.<ref name="davies"/><ref name="sillitto"/><ref name="stanley"/> Several years later Cavendish used a very sensitive [[torsion balance]] to carry out the [[Cavendish experiment]] and determine the average density of Earth.<ref name="tretkoff">{{Cite web|url=http://www.aps.org/publications/apsnews/200806/physicshistory.cfm|title=This Month in Physics History June 1798: Cavendish weighs the world|last=Tretkoff|first=Ernie|publisher=[[American Physical Society]]|access-date=2011-01-03}}</ref>

==In culture==

===Name===
It is unlikely that Mason and Dixon ever heard the phrase "Mason–Dixon line". The official report on the survey, issued in 1768, did not even mention their names.<ref name = WaPo /> While the term was used occasionally in the decades following the survey, it came into popular use during congressional debates on the [[Missouri Compromise]] named "Mason and Dixon's line" as part of the boundary between slave territory and free territory.<ref>{{cite web|first=John|last=Mackenzie|url=http://www1.udel.edu/johnmack/mason_dixon/|title=A brief history of the Mason–Dixon Line|archive-url=https://web.archive.org/web/20180717185851/http://www1.udel.edu/johnmack/mason_dixon/ |archive-date=July 17, 2018|website=APEC/CANR, University of Delaware|access-date=2017-01-05}}</ref>

===Symbolism===
In popular usage to people from the United States, the Mason–Dixon line symbolizes a [[cultural boundary]] between the [[Northeastern United States|North]] and the [[Southern United States|South]] ([[Dixie]]). Originally "Mason and Dixon's Line" simply referred to the border between Pennsylvania (including "the Delaware Counties") and Maryland. However, it has been used metaphorically to describe the entire boundary between slave and free states during the 19th-century. After [[History of slavery in Pennsylvania|Pennsylvania abolished slavery]], it served as a demarcation line for the legality of [[slavery in the United States|slavery]]. Technically, that demarcation did not extend beyond Pennsylvania where Virginia, Maryland, and Delaware, all [[slave states]], lay south or east of the boundary. Also lying north and east of the boundary was [[History of slavery in New Jersey|New Jersey]], where slavery was formally abolished in 1846, but former slaves continued to be "apprenticed" to their masters until the passage of the [[Thirteenth Amendment to the United States Constitution]] in 1865.

The Missouri Compromise line ([[Parallel 36°30′ north]]) had a much clearer geographic connection to slavery in the [[History of the United States (1849–1865)|United States leading up to the Civil War]].<ref name=ColoradoTerritory>{{cite web |url=http://www.colorado.gov/dpa/doit/archives/territory.pdf |title=An Act to provide a temporary Government for the Territory of Colorado |publisher=[[Thirty-sixth United States Congress]] |date=February 28, 1861 |access-date=2007-02-22}}</ref>

===In popular culture===
{{in popular culture|date=June 2020}}
Popular culture contains a multitude of references to the Mason–Dixon line as a general geographic division, or character names evoking it, although a minority of those specifically relate to the line itself.

====Film====
* Mason "The Line" Dixon is a leading character in ''[[Rocky Balboa (film)|Rocky Balboa]]'' (2006),<ref>{{cite web|website=The Internet Movie Database |date=2006|title=Rocky Balboa|url=https://www.imdb.com}}</ref> the sixth film in the [[Rocky (film series)|Rocky franchise]], directed by and starring [[Sylvester Stallone]]. Played by real-life boxer [[Antonio Tarver]], Dixon is the current [[World Heavyweight Boxing Champion]] who is ridiculed for having never fought a real contender, and who thus agrees to an exhibition fight against the nearly 60-year-old [[Rocky Balboa]].<ref>{{cite news|work=Empire Magazine |title=Film Review|date=2007}}</ref>
* In ''[[Attack of the Killer Tomatoes]]'' (1978), Mason Dixon is the leader of a government task force dedicated to stopping the worldwide crisis when tomatoes turn malignant.<ref>{{cite web|url=http://www.bonappetit.com/entertaining-style/pop-culture/article/attack-of-the-killer-tomatoes-an-oral-history-of-the-1978-film|title=Attack of the Killer Tomatoes: An Oral History of the 1978 Film|first=Sam|last=Dean|date=August 8, 2013 }}</ref>

====Cartoons====
* The line makes several appearances<ref>{{cite web|website=yosemite-sam.net/ |date=2017|title= still from the cartoon "southern fried rabbit" showing the line |url=http://yosemite-sam.net/Sam/Animated-Cartoons/Southern-Fried-Rabbit-04.JPG}}</ref> in the 1953 [[Bugs Bunny]] cartoon "[[Southern Fried Rabbit]]". The line separates the drought-affected North from which the "Yankee" Bugs leaves in search of carrots in the green lands of the "Dixie" South, the latter being guarded by [[Yosemite Sam]], who thinks the Civil War is still ongoing.

====Literature====
* In the novel ''[[The People's Choice (novel)|People's Choice]]'' by [[Jeff Greenfield]], the character of W. Dixon Mason is an African-American preacher who plays a major role in determining the next U.S. president when the elected candidate dies between the popular election and the [[Electoral College (United States)|Electoral College]] formal vote.<ref>{{cite web|url=http://www.publishersweekly.com/978-0-399-13812-6|title=Fiction Book Review: People's Choice by Jeff Greenfield, Author Putnam Publishing Group (309p) |date=September 1995 }}</ref>{{better source needed|date=June 2016}}
* ''[[Mason & Dixon]]'' (1997) is the title of a novel by American author [[Thomas Pynchon]].<ref>{{cite news|work=The New York Times |title= Book review – Mason & Dixon |date= 1997 }}</ref> The novel meanders widely through the lives of Mason and Dixon, traditional American history, and other themes such as [[hollow earth theory]], [[geomancy]], [[deism]], and{{spaced ndash}}perhaps{{spaced ndash}}[[alien abduction]].<ref>{{cite web|title=Mason & Dixon |website=ThomasPynchon.com|url=http://www.thomaspynchon.com}}</ref>

====Music====
* The 1918 song, "[[Rock-a-Bye Your Baby with a Dixie Melody]]", written by [[Jean Schwartz]], [[Sam M. Lewis]], and [[Joe Young (lyricist)|Joe Young]], popularized by [[Al Jolson]], includes the lyric "Just hang my cradle, Mammy mine/ Right on that Mason–Dixon Line".<ref>Sheet music (copyright 1918) viewable at https://levysheetmusic.mse.jhu.edu/collection/154/093</ref>
* A small group of musicians from Paul Whiteman's orchestra led by C melody saxophonist [[Frank Trumbauer]] and including [[Bix Beiderbecke]] recorded two sides for Columbia on May 15, 1929, titled, "Alabammy Snow" and "What A Day!" under the pseudonym, "Mason–Dixon Orchestra".<ref>Discography of American Historical Recordings, s.v. "Columbia 1861-D (10-in. double-faced)", accessed August 30, 2017, http://adp.library.ucsb.edu/index.php/object/detail/196765/Columbia_1861-D.</ref> It is probable that they chose this pseudonym because the catalog number of the record would be 1861-D, 1861 being the year that the American Civil War began.
* The lyric "First to cross the Mason–Dixon line" featured in the opening verse of the song "I've Done it Again" (composers [[Marianne Faithfull]] / [[Barry Reynolds]]) on [[Grace Jones]]' 1981 album ''[[Nightclubbing (Grace Jones album)|Nightclubbing]]''.<ref>{{cite web|url=https://genius.com/Grace-jones-ive-done-it-again-lyrics|title=Grace Jones – I've Done It Again|via=genius.com}}</ref>
* The 1955 song, "[[Hey, Porter]]", by [[Johnny Cash]] makes reference to the Mason–Dixon line in the line, ''How much longer will it be 'til we cross that Mason-Dixon line?''<ref>{{cite web|url=https://www.johnnycash.com/track/hey-porter/|title=Johnny Cash|access-date=June 24, 2024}}</ref>
* From the 2000 album ''[[Sailing to Philadelphia]]'' by British singer-songwriter and guitarist [[Mark Knopfler]], the title track (also featuring [[James Taylor]]) is about the two English surveyors Charles Mason and Jeremiah Dixon travelling to Philadelphia to survey the Mason–Dixon line; the lyrics draw from ''[[Mason & Dixon]]'' by [[Thomas Pynchon]], a novel about their relationship.<ref>[[Sailing to Philadelphia]]</ref>{{Circular reference|date=February 2025}}
* [[Sonic Youth]]'s "Paper Cup Exit" from the album ''[[Sonic Nurse]]'' (2004) has the line "Touch down on the new Mason-Dixon line" (sung by [[Lee Ranaldo]])
* [[Dan Seals]] sang ''"Mason Dixon line"'' and the song symbolically references the line.<ref>{{cite web|url=https://genius.com/Dan-seals-mason-dixon-line-lyrics|title=Mason Dixon Line|access-date=24 Oct 2019}}</ref>
* [[GZA]] references the ''"Mason-Dixon Line"'' in the closing words of his feature verse on [[Raekwon|Raekwon's]] song ''"Guillotine (Swords)"'' from his debut 1995 album ''[[Only Built 4 Cuban Linx...|Only Built 4 Cuban Linx]]''.<ref>{{Citation|title=Raekwon (Ft. Ghostface Killah, GZA & Inspectah Deck) – Guillotine (Swordz)|url=https://genius.com/Raekwon-guillotine-swordz-lyrics|language=en|access-date=2019-05-23}}</ref>
* [[Tom Lehrer]] references the Mason–Dixon line in his song "[[Songs by Tom Lehrer|I Wanna Go Back to Dixie]]".<ref>{{cite web|url=https://genius.com/Tom-lehrer-i-wanna-go-back-to-dixie-lyrics|title=I Wanna Go Back to Dixie|access-date=24 Oct 2019}}</ref>
* [[Lady A]]ntebellum's eponymous album has a song "Home Is Where The Heart Is", which contains the line "It's just south of the Mason-Dixon line".<ref>{{Cite web|url=https://www.metrolyrics.com/home-is-where-the-heart-is-lyrics-lady-antebellum.html|title=Lady Antebellum "Home Is Where The Heart Is" Lyrics|access-date=March 17, 2020|archive-date=March 18, 2020|archive-url=https://web.archive.org/web/20200318024740/https://www.metrolyrics.com/home-is-where-the-heart-is-lyrics-lady-antebellum.html|url-status=dead}}</ref>
* The 1916 song "[[Are You from Dixie ('Cause I'm from Dixie Too)]]" originally recorded by [[Billy Murray (singer)|Billy Murray]] contains the lyrics "If you're from Alabama, Tennessee, or Caroline. Any place below the Mason-Dixon line. Then you're from Dixie."<ref>{{Cite journal|url=https://digitalcommons.conncoll.edu/sheetmusic/116|title=Are You from Dixie? ('Cause I'm from Dixie Too)|first1=Jack|last1=Yellen|first2=George|last2=Cobb|date=January 1, 1915|journal=Historic Sheet Music Collection}}</ref>
* Brad Paisley, LL Cool J, and Lee Thomas Miller's controversial 2013 song "[[Accidental Racist]]" uses the Mason–Dixon line as a metaphor for north–south, black/white, and other cultural (dysfunctional) relations: "Oh, Dixieland/The relationship between the Mason-Dixon needs some fixin'"<ref>{{cite magazine|accessdate=2021-04-14|title=Brad Paisley's 'Accidental Racist': LL Cool J's 10 Craziest Lyrics|url=https://www.billboard.com/music/pop/brad-paisleys-accidental-racist-ll-cool-js-10-craziest-lyrics-1556654/|date=8 April 2013|magazine=Billboard}}</ref>
* [[David Allan Coe]] sings about the Mason–Dixon line in "I Still Sing the Old Songs".
* [[Connie Smith]] sings about the Mason–Dixon Line in "Cincinnati, Ohio", with lyrics by [[Bill Anderson (singer)|Bill Anderson]].
* The 1983 song [[Dixieland Delight]] by country singer [[Ronnie Rogers]] and recorded by American [[country music]] band [[Alabama (band)|Alabama]] references the Mason-Dixon Line multiple times throughout the song.<ref>{{cite web |title=Dixieland Delight |url=https://genius.com/Alabama-dixieland-delight-lyrics |website=Genius |access-date=8 May 2022}}</ref>
* The country band [[Mason Dixon (band)|Mason Dixon]]<ref name="allmusic">{{cite web | url=https://www.allmusic.com/artist/mason-dixon-mn0002141765 | title=Mason Dixon biography | publisher=AllMusic | accessdate=March 1, 2021}}</ref>
* The 2022 song, "Before" which is included in the album [[Nicole (album)|Nicole]], written by [[Niki (singer)|NIKI]] includes the lyric "While you stay just fine and feel alive south of the Mason-Dixon line".<ref>{{Citation |title=NIKI – Before |url=https://genius.com/Niki-before-lyrics |access-date=2023-05-24}}</ref>
* In [[Kathy Mattea]]'s 1986 song "Leaving West Virginia", she is leaving her home state for California in search of success, but indicates that "I'll surely leave my heart below the Mason-Dixon line".<ref>{{cite web|title=Kathy Mattea - Leaving West Virginia|url=https://genius.com/Kathy-mattea-leaving-west-virginia-lyrics|date=1986}}</ref>
* The 2008 song "Ruby and Carlos" by [[James McMurtry]] from the album ''[[Just Us Kids]]'' opens with the lines "Ruby said you're getting us in of world of hurt, Down below the Mason-Dumbass line the food gets worse"

====Sports====
* In the regional baseball rivalry between [[Yankees–Red Sox rivalry|the New York Yankees and the Boston Red Sox]], the theoretical border that separates population centers that are majority-Red Sox fans from majority-Yankees fans in [[Connecticut]] is sometimes called the "Munson-Nixon Line",<ref name=":0">{{Cite news|url=https://www.nytimes.com/interactive/2014/04/23/upshot/24-upshot-baseball.html|title=Up Close on Baseball's Borders|last1=Giratikanon|first1=Tom|date=2014-04-24|work=The New York Times|access-date=2017-10-25|last2=Katz|first2=Josh|language=en-US|issn=0362-4331|last3=Leonhardt|first3=David|last4=Quealy|first4=Kevin}}</ref><ref>{{Cite news|url=https://www.si.com/vault/2013/12/16/106408077/reconcilable-differences|title=Reconcilable Differences|last=Rushin|first=Steve|work=SI.com|access-date=2017-10-25}}</ref><ref>{{Cite news|url=https://spectator.org/baseballs-borders/|title=Baseball's Borders|date=2014-04-25|work=The American Spectator|access-date=2017-10-25|language=en-US}}</ref> in a (somewhat parodic) reference to the Mason–Dixon line. Credited to [[Steve Rushin]] of ''[[Sports Illustrated]]'',<ref name=":0" /> the line is named for famed Yankee catcher [[Thurman Munson]] and Red Sox right fielder [[Trot Nixon]]. In the book ''[[The Nine Nations of North America]]'', this line is mentioned (but not named) as the true marker of whether a given location in Connecticut is socially part of New England or the [[rust belt]] region the author calls The Foundry.<ref>{{cite book|author=Joel Garreau|year=1981|title=The Nine Nations of North America|url=https://archive.org/details/ninenationsofno000garr|url-access=registration|publisher=Houghton Mifflin|isbn=0395291240|page=17}}</ref> This line has moved over the years, but it's still there.

==See also==
{{Portal|Philadelphia}}
* [[Collins–Valentine line]], the boundary between the province of Quebec and the states of New York and Vermont
* [[Delaware Boundary Markers]]
* [[Penn–Calvert boundary dispute]]
* [[Mason and Dixon Survey Terminal Point]]
* [[Star Gazers' Stone]]
* [[Tofu Curtain]]
* [[49th parallel north]]
* [[Weißwurstäquator]], a similar border line in [[Germany]] between the [[Northern Germany|Northern]] and [[Southern Germany|Southern]] areas of the country.

==Notes==
{{NoteFoot}}

==References==
{{Reflist}}

==Further reading==
* Danson, Edwin. ''Drawing the Line: How Mason and Dixon Surveyed the Most Famous Border in America''. Wiley. {{ISBN|0471385026}}.
* Ecenbarger, Bill. ''Walkin' the Line: A Journey from Past to Present Along the Mason–Dixon''. M. Evans. {{ISBN|978-0871319623}}.

==External links==
{{Commons category|Mason-Dixon Line}}
{{AmCyc Poster|Mason and Dixon's Line}}
* [http://www.mdlpp.org The Mason and Dixon Line Preservation Partnership] Collection of historical articles and pictures
* [http://collection1.libraries.psu.edu/cdm4/document.php?CISOROOT=/digitalbks2&CISOPTR=11034&REC=13 The Evolution of the Mason and Dixon Line] Facsimile copy of this 1902 text available on-line at Penn State's Digital Bookshelf
* {{Cite NIE|wstitle=Mason and Dixon's Line|year=1905 |short=x}}
* {{Cite EB1911|wstitle=Mason and Dixon Line |short=x}}
* {{Cite NSRW|wstitle=Mason and Dixon's Line |short=x}}
* [https://archive.today/20140505150058/http://www.whiteclayfriends.org/mason_and_dixon.php Mason and Dixon in Mill Creek], Friends of White Clay Creek State Park
* [https://web.archive.org/web/20130524003657/http://southernthings.web.unc.edu/the-mason-dixon-line/ University of North Carolina: Southern Things]
* [https://archive.org/stream/historymasonand00latrgoog#page/n2/mode/2up The history of Mason and Dixon's line]; The Historical Society of Pennsylvania (1855)
* {{HABS |survey=PA-349 |id=pa0027 |title=Mason-Dixon Line Marker, Zora, Adams County, PA |photos=1 |data=1 |supp=yes}}

{{Authority control}}

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