Southwest Pennsylvania Corner Monument, 1883
Posted by: Groundspeak Regular Member Algoma!
N 39° 43.274 W 080° 31.152
17S E 541207 N 4396928
Quick Description: Terminus of the Mason and Dixon Line AND the Ellicott Line, separating West Virgina from Pennsylvania. Monument is somewhat weathered after 124 years in the woods.
Location: Pennsylvania, United States
Date Posted: 8/26/2007 5:53:28 PM
Waymark Code: WM22ZM
Published By: Groundspeak Charter Member GEO*Trailblazer 1
Views: 155

Long Description:
My waymarking / caching partner "Vegy" and I headed from Young Road along the Ellicott Line through thick woods and steep hills .18 miles to this important monument. After scouring a hillside for fifteen minutes, we were both very pleased to see the original 1883 survey stone standing. This site is not often visited since it is within private property. The stone is tilted perhaps five degrees from shifting. It is a slanted obelisk with a truncated pyramidal top. On top it is marked with an engraved "X" which matches compass directions. It seems strange that the western end of the most famous boundary in history (Mason/Dixon) is so understated. I am surprised that PA or WVA have not erected some kind of historical marker on the road. (Perhaps the local land owners donn't want that much attention?)
Monumentation Type: Dressed stone

Monument Category: State boundary marker

Explain Non-Public access:
This monument is on posted private property in two states. We decided to risk the entry and would explain our mission to anyone who might have asked. There's a small private hunting lodge on the way. We did not see anyone the whole time and we also did not see any homes to knock on the door of to ask permission.

Historical significance:
Thanks to "seventhings", fellow waymarker / border monument hunter, for allowing me to use the following historical information which he dilligently researched: In 1782-83, Alexander McLean and Joseph Neville completed Mason and Dixon’s line to the (estimated) limit of five degrees of longitude. In 1784, commissioners and surveyors James Madison, Robert Andrews, John Page and Andrew Ellicott of Virginia, and David Rittenhouse, John Lukens, John Ewing and Thomas Hutchins of Pennsylvania, fixed the southwest corner of Pennsylvania by astronomical observation. To perform this task, the surveyors divided into two parties: one at Wilmington, DE, near the west bank of the Delaware River and the other in the vicinity of the southwest corner of Pennsylvania. They made simultaneous observations of a distinctive celestial event: the eclipse of the moons of Jupiter. By noting the time difference between the simultaneous observations by the two teams, they were able to calculate very accurately both the distance between the two parties in degrees of longitude and the corrections necessary to determine the location of the western end of the line relative to the location of the western observatory. With these values, the surveyors were able to ascertain the location of the west end of the West Line without reference to the actual distance (as would be expressed in feet, rods and miles) from the east end. As a result, they estimated that they were 23 miles west of where Mason and Dixon had left off in 1767. In 1948, Thomas Cope evaluated the 1784 survey’s performance; he determined that their position for the southwest corner of Pennsylvania was 23 feet west of a point exactly five degrees of longitude from the west bank of the Delaware River. He also noted that the position was 22 miles west of Brown’s Hill. In 1785-86, Andrew Ellicott ran a meridian northward from the southwest corner of PA first to the Ohio River (to establish PA’s western boundary line with Virginia – now, West Virginia) and, second, to the southern bank of Lake Eire (to establish PA’s western boundary with the “Northwest Territories”). The meridian forming PA’s western boundary line is one of two “Ellicott Lines”, the other being the boundary between the United States and the Spanish Territory of Florida (now the boundary between the states of Alabama and Florida). Starting in 1785, Thomas Hutchins, Geographer of the United States, used that portion of the PA Ellicott Line extending north from the Ohio River as the base line for the first US Public Land Survey. In 1883-85, joint boundary commissioners Col. James Worrell, James McCullough, and William Walker of Pennsylvania, and Joseph Gist, Capt. John Chipley and Francis L. Hoge of West Virginia, engaged Cephas Sinclair and C. H. Van Orden of the US Coast and Geodetic Survey, re-surveyed the Ellicott Line for the 63.6 miles from the Ohio River to the southwest corner of PA, and the West Line from (their estimate of) the northwest corner of MD for the 55.2 miles to the southwest corner of PA. The commissioners (McCullough, Chipley and Hoge) set 47 new boundary monuments (48 were planned) along the meridian, and 40 new boundary monuments (41 were planned) along the West Line, including a monument at the intersection of the two lines. Their eastern-most monument (the “Sinclair Stone” at Sinclair’s estimate of the PA-WV-MD tri-state boundary intersection point) lies 0.75 miles east of a monument established by the US Corps of Topographic Engineers in 1860, and 0.20 miles east of the intersection point as established by a survey directed by the US Supreme Court in 1910.


Approximate date of monument: 12/12/1883

Monumentation Type (if other): Not listed

Monument Category (if other): Not listed

Accessible to general public: Not Listed

Monument Website: Not listed

USGS Quad: Not listed

NGS PID: Not listed

Other Coordinates: Not Listed

Other Coordinates details: Not listed

Visit Instructions:
1. A closeup photo of the monument is required.
2. A 'distant' photo including the monument in the view is highly recommended. Include the compass direction you faced when you took the picture.
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swpa_cacher visited Southwest Pennsylvania Corner Monument, 1883 3/4/2006 swpa_cacher visited it

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