Star Gazers' Stone located on Star Gazers' Farm near
Embreeville, Pennsylvania
Embreeville is a historical Unincorporated area#United States, unincorporated community, little more than a rural stretch of road with a few businesses and homes, in Newlin Township, Pennsylvania, United States, on a bend of Brandywine Creek (C ...
,
USA
The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 states and a federal capital district, Washington, D.C. The 48 contiguous ...
, marks the site of a temporary observatory established in January 1764 by
Charles Mason
Charles Mason (25 April 1728[Jeremiah Dixon
Jeremiah Dixon (27 July 1733 – 22 January 1779), British surveyor and astronomer, created the Mason–Dixon line with Charles Mason, from 1763 to 1767, which became significant during the American Civil War.
Early life and education
Dixon wa ...]
which they used in their survey of the
Mason-Dixon line. The stone was placed by Mason and Dixon about north of the Harlan House, which was used as a base of operations by Mason and Dixon through the four-and-a-half-year-long survey. Selected to be about west of the
then southernmost point in Philadelphia, the observatory was used to determine the precise latitude of its location. The latitude of the
Maryland
Maryland ( ) is a U.S. state, state in the Mid-Atlantic (United States), Mid-Atlantic region of the United States. It borders the states of Virginia to its south, West Virginia to its west, Pennsylvania to its north, and Delaware to its east ...
-
Pennsylvania
Pennsylvania, officially the Commonwealth of Pennsylvania, is a U.S. state, state spanning the Mid-Atlantic (United States), Mid-Atlantic, Northeastern United States, Northeastern, Appalachian, and Great Lakes region, Great Lakes regions o ...
border was then set to be south of the point in Philadelphia. The farm, including the house and stone, were listed on the
National Register of Historic Places
The National Register of Historic Places (NRHP) is the Federal government of the United States, United States federal government's official United States National Register of Historic Places listings, list of sites, buildings, structures, Hist ...
on May 9, 1985. In 2013 construction was completed on a parking area to allow public access to Star Gazers Stone.
Built c. 1724 near the forks of the
Brandywine, the Harlan House was enlarged c.1758, and is likely the first house built in
Newlin Township. The Harlan family lived in the house until 1956, and carefully preserved the location of the stone through the generations.
[Roby]
The observatory

Mason and Dixon's survey was the final step in the resolution of a border dispute between Pennsylvania and Maryland that lasted over 80 years. From 1730-1738 a violent border conflict, known as
Cresap's War
Cresap's War (also known as the Conojocular War, from the Conejohela Valley where it was mainly located along the south bank) was a border conflict between Pennsylvania and Maryland fought in the 1730s. Hostilities erupted in 1730 with a serie ...
, was fought between Pennsylvania and Maryland. In 1760 the Crown intervened, defining the border as the line of latitude south of the southernmost house in Philadelphia. The proprietors of the colonies, the Penns and Calverts, then commissioned Mason and Dixon to
survey the newly established boundary.
Mason and Dixon used the finest instruments of their day in the survey, including a type of telescope, the
zenith sector built by
John Bird, used for measuring latitude and an "
equal altitude and transit" instrument for sighting survey lines, as well as a less accurate
quadrant
Quadrant may refer to:
Companies
* Quadrant Cycle Company, 1899 manufacturers in Britain of the Quadrant motorcar
* Quadrant (motorcycles), one of the earliest British motorcycle manufacturers, established in Birmingham in 1901
* Quadrant Privat ...
for faster rough estimates of latitude, and a
chronometer built by
John Harrison
John Harrison ( – 24 March 1776) was an English carpenter and clockmaker who invented the marine chronometer, a long-sought-after device for solving the History of longitude, problem of how to calculate longitude while at sea.
Harrison's sol ...
, used for measuring longitude. Though Harrison's chronometers later became the standard instrument for measuring longitude, the surveyors' job was mainly to measure latitude, and Mason preferred the
method of lunar distance of measuring longitude to the new method.
On December 9, 1763 soon after arriving in Philadelphia, the surveyors received their instructions from the joint border commission:
The first instruction was completed by January 6, 1764 by constructing an observatory near the Huddle-Plumstead House on Cedar Street (now named
South Street
South Street may refer to:
Streets by that name
* South Street (Durham), England
* South Street, Mayfair, England
*South Street (Manhattan), United States
*South Street (Perth, Western Australia)
* South Street (Perth, Scotland)
*South Street (Ph ...
) in Philadelphia, and measuring the angle of the zenith of eight stars. Rather than measure directly south of Philadelphia to start the survey, a westward move was needed to avoid crossing the wide Delaware River twice, and to avoid beginning the survey of the Pennsylvania-Maryland border in New Jersey.
[Danson, p.93]
The surveyors fulfilled the second instruction by January 13, as recorded in their journal:

The new site of the observatory was near marks that had been made by surveyors from New Jersey in 1730 and 1736.
By February 28 Mason and Dixon had determined the latitude at Star Gazers' Stone by observing the eight stars. After making adjustments for the distance their observatory was south of Philadelphia, Mason and Dixon measured south to a point in Delaware by April 21. They moved the observatory to this point where they measured the latitude again and remeasured back to the Star Gazers' Stone. In May and June they again measured the latitude at Star Gazers' Stone. The southern point was named the "Post mark'd west" and the Maryland-Pennsylvania border was, after a delay, measured straight west from there.
Mason and Dixon returned to the house many times during the four and one-half years of the survey, often spending the winters there.
[Ecenbarger, pp. 120-122] On January 1, 1767, Mason recorded a temperature of minus 22 degrees
Fahrenheit
The Fahrenheit scale () is a scale of temperature, temperature scale based on one proposed in 1724 by the German-Polish physicist Daniel Gabriel Fahrenheit (1686–1736). It uses the degree Fahrenheit (symbol: °F) as the unit. Several accou ...
at the farm. They returned to the observatory when they started the new task of measuring the distance of a degree of latitude in miles. They were reputed to be heavy drinkers, and local lore says that a nearby tributary of the Brandywine, Punch Run Creek, was named to commemorate their drinking. At the end of the survey, the Harlan house was one of the last places they visited before returning to Britain via Philadelphia.
The Harlan house and farm
Brothers George and Michael Harlan were
Quakers
Quakers are people who belong to the Religious Society of Friends, a historically Protestantism, Protestant Christian set of Christian denomination, denominations. Members refer to each other as Friends after in the Bible, and originally ...
who were born in
Durham Durham most commonly refers to:
*Durham, England, a cathedral city in north east England
**County Durham, a ceremonial county which includes Durham
*Durham, North Carolina, a city in North Carolina, United States
Durham may also refer to:
Places
...
,
England
England is a Countries of the United Kingdom, country that is part of the United Kingdom. It is located on the island of Great Britain, of which it covers about 62%, and List of islands of England, more than 100 smaller adjacent islands. It ...
and immigrated to Pennsylvania about 1687 from
County Down
County Down () is one of the six counties of Northern Ireland, one of the nine counties of Ulster and one of the traditional thirty-two counties of Ireland. It covers an area of and has a population of 552,261. It borders County Antrim to the ...
,
Ireland
Ireland (, ; ; Ulster Scots dialect, Ulster-Scots: ) is an island in the North Atlantic Ocean, in Northwestern Europe. Geopolitically, the island is divided between the Republic of Ireland (officially Names of the Irish state, named Irelan ...
. Michael's son George Harlan built the house in the forks of the Brandywine c.1724. In that year the Free Society of Traders sold to
Nathaniel Newlin, which became
Newlin Township in
Chester County Chester County may refer to:
* Chester County, Pennsylvania, United States
** Chester County Council, boy scout council in Pennsylvania.
* Chester County, South Carolina, United States
* Chester County, Tennessee, United States
* Cheshire
...
. Newlin immediately sold some of the land, including in the forks of Brandywine Creek sold to George Harlan. A son, Joel, was born to George and Mary Harlan in 1724 in Newlin Township, presumably in their new house. The house was probably the first in the township. Tax assessments in the township were first made in 1739, and until 1760, Joel's older brother John Harlan paid the taxes on the house and farm. Sometime between 1758 and 1760 Joel returned to Newlin Township after living in other locations in Chester County, took ownership of the farm and built an addition to the house. Both John's and Joel's families apparently lived in the same house, but Mason and Dixon's Journal always refers to the "John Harland farm" or simply the "Harland farm." John Harlan died by drowning in the Brandywine in 1768.
The original house is two stories measuring by , constructed of stone. The c.1758 addition was also constructed of stone and measures by . A small frame addition was built in the nineteenth century.
The Harlan family lived on site until they sold the property in 1956. In 1908 the Chester County Historical Society dug up the Star Gazers' Stone, set it in concrete, built a low stone wall around it, and placed a plaque on the new wall. At the dedication, Henry K. Harlan said that each generation of the family was taught that the Star Gazers' Stone had an important place in American history and that they should not move the stone.
Natural Lands the region's foremost land conservation organization, now owns the stone as part of ChesLen Preserve, which is open to the public.
Joshua Harlan, son of the immigrant George Harlan, built a log cabin known as the
Harlan Log House
The Harlan Log House, also known as "The Log House," was built about 1715 by Joshua Harlan, is a well-preserved example of an English-style log cabin near Kennett Square, in Kennett Township, Chester County, Pennsylvania, United States. It is ...
about 1715, about south in
Kennett Township which is also listed on the National Register of Historic Places.
See also
*
Josiah Harlan
Josiah Harlan, Prince of Ghor (June 12, 1799 – October 1871) was an American adventurer who travelled to Afghanistan and Punjab with the intention of making himself a king. During his travels, he became involved in local politics and factio ...
- Joel's grandson
*
Mason and Dixon Survey Terminal Point
*
Natural Lands
Natural Lands is a non-profit land conservation organization with headquarters in Media, Pennsylvania, dedicated to the management, protection, and conservation of eastern Pennsylvania and southern New Jersey, New Jersey's native forests, fields, ...
*
Penn–Calvert boundary dispute
The Penn–Calvert boundary dispute (also known as ''Penn vs. Baltimore'') was a long-running legal conflict between William Penn and his heirs on one side, and Charles Calvert, 3rd Baron Baltimore and his heirs on the other side. The overlapping ...
*
White Clay Creek State Park
White Clay Creek State Park is a Delaware state park along White Clay Creek on in New Castle County, near Newark, Delaware in the United States. North of the park is Pennsylvania's White Clay Creek Preserve, and the two were originally opera ...
, site of "Post mark'd west"
References
Sources
*
*
* p. 158
*, Chapter: John Russell Hayes - Star Gazers' Stone, pp 93–101.
*Roby, Thomas C. (1984), National Register of Historic Places,
Inventory - Nomination Form, Star Gazers House pp. 6. Enter "public" for ID and "public" for password to access the site.
External links
Historical markers database History and Heritage of Civil Engineering - Mason-Dixon Line*
{{National Register of Historic Places in Pennsylvania
Buildings and structures on the National Register of Historic Places in Pennsylvania
Buildings and structures in Chester County, Pennsylvania
Surveying of the United States
History of the Thirteen Colonies
National Register of Historic Places in Chester County, Pennsylvania
Mason–Dixon line