The Southern Observer

Geography

Mason and Dixon's actual survey line began 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 (now the state of West 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 a true east-west line. The surveyors also drew the boundary line between Pennsylvania and colonial western Virginia—modernly, the boundary between the Commonwealth of Pennsylvania and states of West Virginia and Ohio (both of which lay in colonial Virginia's territorial claim under her royal charter, but the lands north of the Ohio River and west of a line later drawn through the Appalachian Mountains were surrendered by Virginia subsequent to adoption of the U.S. Constitution in 1789 and organization of the Northwest Territory).

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

Mason and Dixon confirmed earlier survey work which delineated Delaware's southern boundary from the Atlantic Ocean to the ”Middle Point” stone. 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 NOAA, the corner of PA-MD-DE at The Wedge is 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.


History

The original 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 below 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:

Diagram of the survey lines creating the Mason-Dixon Line and the "Wedge"

The existing east-west Transpeninsular Line from the Atlantic Ocean to its mid-point to the Chesapeake Bay.

A "Tangent Line" from the mid-point of the Transpeninsular Line to the western side of a twelve-mile circle around Newcastle.

A "North Line" along the meridian from the tangent point to a line running 15 miles south of Philadelphia (about 39° 43' N latitude).

The parallel at 39° 43' N was agreed as the Maryland–Pennsylvania line.

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.

The Mason–Dixon "line" is actually 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.

Mason and Dixon then surveyed the more famous Maryland-Pennsylvania line.

They were supposed to run it for a distance of five degrees of longitude west from the Delaware River (fixing the western boundary of Pennsylvania). However, 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 and 1785, other surveyors continued the line about 36 miles farther west, past the western border of Pennsylvania, to the Ohio River, to settle the border dispute between Pennsylvania and Virginia (see the entry for Yohogania County.) 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.

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 to be his last public appearance before his assassination in Dallas, Texas 8 days later. The Delaware Turnpike and the Maryland portion of the new road were each later designated as the John F. Kennedy Memorial Highway.


Cultural references

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

The Jerry Reed tune "Are You From Dixie" references some states south of the Mason-Dixon-Line.

The animated short film "Southern Fried Rabbit" features Bugs Bunny and Yosemite Sam and takes place on the Mason-Dixon Line — literally, on it.

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.

Thomas Pynchon has written a fictional book about the construction of the Mason-Dixon Line named Mason & Dixon, first published in 1997. This book makes no claim of being historically rigorous.

Mark Knopfler sings 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.

The band Empire Falls makes a reference to the Mason-Dixon Line in their song "Kudzu Alley," off the album "The Underdogs." The song also includes a reference to carpetbaggers.