Mason-Dixon Line

Mason-Dixon Line

The Mason–Dixon Line (or "Mason and Dixon's Line") is a demarcation line between four U.S. states, forming part of the borders of Pennsylvania, Maryland, Delaware, and West Virginia (then part of Virginia). It was surveyed between 1763 and 1767 by Charles Mason and Jeremiah Dixon in the resolution of a border dispute between British colonies in Colonial America. Popular speech, especially since the Missouri compromise of 1820 (apparently the first official usage of the term "Mason's and Dixon's Line"), uses the Mason-Dixon Line symbolically as a cultural boundary between the Northern United States and the Southern United States (Dixie).Fact|date=May 2007


Maryland and Pennsylvania both claimed the land between the 39th and 40th parallels according to the charters granted to each colony. The 'Three Lower Counties' (Delaware) along Delaware Bay moved into the Penn sphere of settlement, and later became the Delaware Colony, a satellite of Pennsylvania.

In 1732 the proprietary governor of Maryland, Charles Calvert, 5th Baron Baltimore, signed an agreement with William Penn's sons which drew a line somewhere in between, and also renounced the Calvert claim to Delaware. But later Lord Baltimore claimed that the document he 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 between Pennsylvania and Maryland would be known as Cresap's War.

The issue was unresolved until the Crown intervened in 1760, ordering Frederick Calvert, 6th Baron Baltimore to accept the 1732 agreement. As part of the settlement, the Penns and Calverts commissioned the English team of Charles Mason and Jeremiah Dixon to survey the newly established boundaries between the Province of Pennsylvania, the Province of Maryland, Delaware Colony and parts of Colony and Old Dominion of Virginia.

After Pennsylvania abolished slavery in 1781, the western part of this line and the Ohio River became a border between free and slave states, although Delaware remained a slave state.


Mason and Dixon's actual survey line began to the south of Philadelphia, Pennsylvania, and extended from a 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 a circular 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.

The Maryland–Pennsylvania boundary is an east-west line with an approximate mean latitude of 39° 43' 20" N (Datum WGS 84). In reality, the east-west Mason-Dixon line is not a true line in the geometric sense, but is instead a series of many adjoining lines, following a path between latitude 39° 43' 15" N and 39° 43' 23" N; a surveyor or mapper might call it an approximate rhumb line. As such, the line approximates a segment of a small circle upon the surface of the (also approximately) spherical Earth. An observer standing on such a line and viewing its path toward an unobstructed horizon would perceive it to bend away from his line of sight, an effect of the inequality between the amount of curvature to his left and right. Among parallels of latitude, only the Equator is a great circle and would not exhibit this effect.The surveyors also extended the boundary line to run between Pennsylvania and colonial western Virginia (which became West Virginia during the American Civil War, on June 20, 1863), though this was contrary to their original charter; this extension of the line was only confirmed later (see Yohogania County for details).

The Mason–Dixon Line was marked by stones every mile and ”crownstones” every five miles, using stone shipped from England. The Maryland side says (M) and the Delaware and Pennsylvania sides say (P). Crownstones include the two coats-of-arms. Today, while a number of the original stones are missing or buried, many are still visible, resting on public land and protected by iron cages.

Mason and Dixon confirmed earlier survey work which delineated 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.

Later the line was marked in places by additional benchmarks and survey markers. The lines have been resurveyed several times over the centuries without substantive changes to Mason and Dixon's work. The stones may be a few to a few hundred feet east or west of the point Mason and Dixon thought they were; in any event, the line drawn from stone to stone forms the legal boundary.

According to Dave Doyle at the National Geodetic Survey, part of the National Oceanic and Atmospheric Administration, the common corner of Pennsylvania, Maryland, and Delaware, at The Wedge is marked by Boundary Monument #87. The marker ”MDP Corner” dates from 1935 and is offset on purpose.

Doyle said the Maryland–Pennsylvania Mason–Dixon Line is exactly:

: 39° 43′ 19.92216″ N

and Boundary Monument #87 is on that parallel, at:

: 075° 47′ 18.93851″ W.

Visitors to the tripoint are strongly encouraged to first obtain permission from the nearest landowner.


The line was established to end a boundary dispute between the British colonies of Maryland and Pennsylvania/Delaware. Due to incorrect maps and confusing legal descriptions, the royal charters of the three colonies overlapped. Maryland was granted the territory north of the Potomac River/Watkins Point up to the fortieth parallel; Pennsylvania was granted land extending northward from a point "12 miles north of New Castle Towne," which is located south of the fortieth parallel. The most serious problem was that the Maryland claim would put Philadelphia, which became the major city in Pennsylvania, within Maryland. A protracted legal dispute between the Calvert family, which controlled Maryland, and the Penn family, which controlled Pennsylvania and the "Three Lower Counties" (Delaware), was ended by the 1750 ruling that the boundary should be fixed as follows:

* Between Pennsylvania and Maryland:
** The parallel (latitude line) fifteen miles (24 km) south of the 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 its mid-point to the Chesapeake Bay.
** A Twelve Mile (radius) Circle around the city of New Castle, Delaware.
** A "Tangent Line" connecting the mid-point of the Transpeninsular Line to the western side of the Twelve-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 Twelve-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. It cost the Calverts of Maryland and the Penns of Pennsylvania the immense sum of £3,500 to have 244 miles surveyed with such accuracy. To them the money was well spent, for in a new country there was no other way of establishing ownership. [Linklater, Andro, "Measuring America",(Peguin, 2003), p. 33]

The Mason–Dixon line is made up of four segments corresponding to the terms of the settlement: Tangent Line, North Line, Arc Line, and 39° 43' N parallel. The most difficult task was fixing the Tangent Line, as they had to confirm the accuracy of the Transpeninsular Line mid-point and the Twelve-Mile Circle, determine the tangent point along the circle, 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 of land in dispute between Delaware and Pennsylvania until 1921.

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 244 miles (392 km) west of the Delaware, a group of Native Americans forced them to quit their progress. 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. 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 and Wetzel counties, West Virginia.

The boundary between Pennsylvania and Maryland was resurveyed in 1849, then again in 1900.

The Missouri Compromise of 1820 created the political conditions which made the Mason-Dixon Line important to the history of slavery. It was during the Congressional debates leading up to the compromise that the term "Mason-Dixon line" was first used to designate the entire boundary between free states and slave states.

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. It was his last public appearance before the one 8 days later in Dallas, Texas, where he was assassinated. The Delaware Turnpike and the Maryland portion of the new road were each later designated as the John F. Kennedy Memorial Highway.

As a cultural boundary

The states in dark red are almost always included in modern day definitions of the South, while those in medium red are usually included. The striped states are sometimes/occasionally considered Southern. Note that the Mason-Dixon line forms part of the northern boundary of the striped states [cite web| url= | title=UNC-CH surveys reveal where the ‘real’ South lies | author=David Williamson | accessmonthday=22 Feb | accessyear=2007]

The Mason-Dixon line became symbolic of the division between the "free states" and "slave states" from the Missouri Compromise until the end of the American Civil War. Pennsylvania abolished slavery before the end of the American Revolution while Maryland, Delaware, Kentucky, and Missouri remained slave states until the end of the war.

After the Civil War, the line continued to be considered a cultural boundary.Fact|date=November 2007 Some have imagined it continuing westward from Pennsylvania down the Ohio River to the Mississippi River, and crossing the Mississippi to place Arkansas, Louisiana and Texas south of the line. Debate whether border states such as Missouri, Kentucky, Maryland and West Virginia belong on the north or south side of this boundary line continues to this day.

Cultural references

* Thomas Pynchon wrote a historical novel about the construction of the Mason-Dixon Line titled "Mason & Dixon", first published in 1997. This book makes no claim of being historically rigorous; however, as a work of what critic Linda Hutcheon calls "historiographic metafiction," Pynchon's novel interrogates the very notion of historical "rigor" by suggesting that historiography is - like literature - a contingent socio-cultural construct.Fact|date=June 2008
* George MacDonald Fraser referred to the Mason-Dixon Line in the 1994 novel "Flashman and the Angel of the Lord". This contains the obvious error of referring to the Line's latitude as 39' 43" instead of 39° 43'.
* John Updike refers to the Mason-Dixon line in the novel Rabbit, Run, as the only landmark that Rabbit recognizes on a map, as he leaves Pennsylvania.

* The animated short film "Southern Fried Rabbit" (released May 2, 1953) features Bugs Bunny and Yosemite Sam and takes place on the Mason-Dixon Line — literally, "on" it. The cartoon depicts the north as being barren and empty, while the south is lush and green.
* In the film "Pulp Fiction" (first released on October 14, 1994), Butch Coolidge (Bruce Willis) and Marcellus Wallace (Ving Rhames) are captured and imprisoned in "The Mason-Dixon Pawnshop".
* Antonio Tarver plays a character in the 2006 movie "Rocky Balboa" named Mason "The Line" Dixon.
* In the children's film "Little Big League", the announcer rambles off unimportant facts, mentioning that the Angels have been the best team this year away "north of the Mason-Dixon line".

* In several episodes of the American television series "In the Heat of the Night", a roadhouse in Sparta, Mississippi is called "Mason's Dixieline".Fact|date=September 2008
* In the "Family Guy" episode "To Live and Die in Dixie" Peter Griffin refers to the border as the Donna Dixon Line.Fact|date=September 2008
* In "Viva La Bam" during the Civil War Re-enactment episode, Bam pours white chalk on Don Vito and calls it the "Mason Dixon" line for their re-enactment.Fact|date=September 2008
* In one of Robin Williams' comedy segments, he refers to the border as 'the Manson-Nixon Line'.
* In several Warner Brothers Bugs Bunny cartoons, Bugs pops out of his hole at the Mason-Dixon Line to say "I knew I should have made a left at Albuquerque."Fact|date=September 2008

* The song "I Wish I Was in Dixie", written by an Ohioan in 1859, was extremely popular throughout the Civil War. It was said to be one of Lincoln's favorite songs, and, according to historian Cheryl Thurber, Lincoln asked a band to play "Dixie" for crowds gathered outside the White House on the very day the South surrendered [] .

* The song "Rock-a-Bye Your Baby with a Dixie Melody", most famously recorded by Al Jolson, contains the lines "Just hang my cradle, Mammy mine,/Right on that Mason Dixon line/And swing it from Virginia/To Tennessee with all the love that's in ya." []

* The Johnny Cash tune "Hey Porter" has the singer asking the railroad porter how long it will be until the train crosses the Mason-Dixon Line, as he is longing to be back in the South.

* The popular song "Are You From Dixie?" written by Jack Yellen and George L. Cobb in 1915 and recorded by many country artists over the years, including the Blue Sky Boys in the 1930s and Jerry Reed more recently, references some states south of the Mason-Dixon-Line.

* Mark Knopfler and James Taylor sing about the construction of the Mason-Dixon Line in "Sailing to Philadelphia (Sailing to Philadelphia, Mercury Records, 2000)" Knopfler was inspired by Pynchon's book.

* Waylon Jennings & Mel Tillis also have a song out titled "Mason Dixon Lines" that references the line in every verse.

* The musical group Virginia Coalition have a song titled "Mason-Dixon" that makes reference to the historical line.

* The satirist Tom Lehrer mentions the Mason-Dixon line in the song "I Wanna Go Back to Dixie"

* The politically charged band Rage Against the Machine have a reference to "the new line of Mason-Dixon" in the song "Maria" off the album "The Battle of Los Angeles".

* The song "Southern Girl" by Maze contains the lyrics: "...below the Mason-Dixon line / down there where the girls are fine / Sure know how to treat me you just make me feel so good / Southern girl here's to you no one can do it like you do."

* The Country band Lady Antebellum have a song called "Home Is Where The Heart Is" that references the line in the lyrics: "...Mama said home is where the heart is / Just south of the Mason Dixon Line..."

* Christian metalcore band Norma Jean, at one of their live performances, dedicated their song "Memphis Will Be Laid To Waste" to "everyone south of the Mason-Dixon line...and everyone north of it too."

* Country/Southern Rock Band Alabama, in their song Dixieland Delight, sing about classic southern date night: "Make a little lovin', A little turtle dovin' On a Mason-Dixon night."

* Death metal band Arghoslent in the booklets with their albums it states recorded South of the Mason-Dixon line.

* The song Guillotine by Raekwon (Wu-Tang) ends with a reference to the Mason-Dixon line.


External links

* [ The Mason and Dixon Line Preservation Partnership] Collection of historical articles and pictures
* [ The Mason-Dixon Line also is the southern border of Pennsylvania with West Virginia.] Visit locations and see photos from sites along The Line near its western end at the southwest corner of Pennsylvania.
* [ Mason-Dixon Line]
* [ History of the Mason-Dixon Surveys]
* [ The Charter of Maryland] (1632)
* [ Charter for the Province of Pennsylvania] (1681)
* [ Evolution of the Mason-Dixon Line]
* [ The Evolution of the Mason and Dixon Line] - facsimile copy of this 1902 text available on-line at Penn State's Digital Bookshelf
* [ HyperArts' "Mason & Dixon" Web Guide & Concordance]
* [ The Boundary Disputes of Colonial Maryland]


* Danson, Edwin. "Drawing the Line: How Mason and Dixon Surveyed the Most Famous Border in America". Wiley. ISBN 0-471-38502-6.

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Look at other dictionaries:

  • Mason-Dixon line — Line Line, n. [OE. line, AS. l[=i]ne cable, hawser, prob. from L. linea a linen thread, string, line, fr. linum flax, thread, linen, cable; but the English word was influenced by F. ligne line, from the same L. word linea. See {Linen}.] 1. A… …   The Collaborative International Dictionary of English

  • Mason-Dixon line — [mā′sən dik′sən] [after C. Mason & J. Dixon, who surveyed it, 1763 67] boundary line between Pa. & Md., regarded, before the Civil War, as separating the free states from the slave states or, now, the North from the South: also Mason and Dixon s… …   English World dictionary

  • Mason-Dixon Line — 1779, named for Charles Mason and Jeremiah Dixon, English astronomers who surveyed (1763 7) the disputed boundary between the colonial holdings of the Penns (Pennsylvania) and the Calverts (Maryland). It became the technical boundary between free …   Etymology dictionary

  • Mason-Dixon Line — Mason Dix|on Line the Mason Dixon Line the border between the states of Maryland and Pennsylvania in the US. It divided the states of the ↑South, where it was legal to own ↑slaveS, from the states of the ↑North, where it was illegal, until the… …   Dictionary of contemporary English

  • Mason–Dixon Line — For other uses, see Mason Dixon. The original Mason Dixon Line The Mason–Dixon Line (or Mason and Dixon s Line) was surveyed between 1763 and 1767 by Charles Mason and Jeremiah Dixon in the resolution of a border dispute between British colonies… …   Wikipedia

  • Mason-Dixon-Line — Die Mason Dixon Linie Die Mason Dixon Linie, benannt nach dem Astronomen Charles Mason und dem Geometer Jeremiah Dixon, bildet die traditionelle Grenze zwischen den Nord und den Südstaaten der USA. Sie verläuft von …   Deutsch Wikipedia

  • Mason-Dixon line — n. (in the US) the boundary between Maryland and Pennsylvania, taken as the northern limit of the slave owning States before the abolition of slavery. Etymology: C. Mason & J. Dixon, 18th c. English astronomers who surveyed it * * * noun the… …   Useful english dictionary

  • Mason-Dixon Line —    It is generally understood that the Mason and Dixon line divides the North from the South in the Atlantic region of the United States, and it is used as a figure of speech when discussing regional custom and viewpoints of all sorts. Below the… …   Dictionary of eponyms

  • Mason-Dixon line — /may seuhn dik seuhn/ the boundary between Pennsylvania and Maryland, partly surveyed by Charles Mason and Jeremiah Dixon between 1763 and 1767, popularly considered before the end of slavery as a line of demarcation between free and slave states …   Universalium

  • Mason-Dixon Line — /meɪsən ˈdɪksən laɪn/ (say maysuhn diksuhn luyn) noun the boundary between Pennsylvania and Maryland, partly surveyed by Charles Mason and Jeremiah Dixon between 1763 and 1767, popularly considered before the abolition of slavery as a line of… …   Australian-English dictionary

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