Mason and Dixon in Mill Creek

Special Newsletter Supplement - Friends of White Clay Creek State Park (FWCCSP RECORD, Vol. 8, No. 1, April 2005, p. 6)

Most of us associate Mason and Dixon with the line dividing the north and south in the Civil War. Fewer realize that the line that Charles Mason and Jeremiah Dixon created was surveyed from 1763 to 1767 to end 80 years of bitter and sometimes bloody feuding over the boundary between the Maryland colony of the Calverts and the Pennsylvania colony of the Penns. A key location for that survey was on Alexander Bryan’s farm in what is now the Possum Hill section of White Clay Creek State Park.

The story of how the two acclaimed English surveyors came to Bryan’s field begins in 1632 when Charles I of England granted George Calvert the land north of the Potomac River to the 40th degree north latitude, east to the Delaware Bay, and west to the meridian through the source of the Potomac. The grant excluded any previously cultivated land so some of what is presently Delaware would not have been included.

Then in 1681 Charles II granted William Penn all the territory west of New York and New Jersey, south of the 43rd latitude, north of Maryland beginning at the 40th degree north latitude, and north of a 12-mile circle drawn from the city of New Castle.

Both of these grants seem clear enough. However, problems arose. The maps of the time were often inaccurate as to exact locations of boundaries. To the Calverts disadvantage, they had never had their colony’s borders surveyed, and there was no agreement as to where the boundaries should be. They also never developed the portion to the east of the Chesapeake, so their claims to that part were weakened. The Penns were much more aware of where their boundaries actually were. They were upset because the 12-mile circle around New Castle was short of the 40th parallel by 13 miles. This difference would create a severe loss of territory to which the Penns thought they were entitled and could mean that they were without a seaport. The 40th latitude actually goes through the northern part of Philadelphia and present-day Downingtown. When discussions between Penn and Calvert in 1683 failed to settle the border dispute, Penn took action to have the boundaries established for his benefit. His first petition to the Crown resulted in the (Delmarva) peninsula being divided in half lengthwise and the eastern half put under Penn’s control. This area, that is now Delaware, was call the Three Lower Counties of Pennsylvania. (Delaware was granted autonomy in 1701, but remained under Penn's ownership.) As a result the Penns were guaranteed a seaport. The Calverts, on the other hand, had lost much territory.

For the next 80 years the arguments over the boundaries continued with petition and counter petition being sent to London seeking settlement of the very contentious border issues. With each decree, the losing side sent another petition seeking redress. The dispute created a number of problems. Taxes could not be collected in the disputed territories; residents who wanted to be in one colony sometimes attacked surveyors who they thought were representing the other colony; and some residents along the disputed borders were in armed conflict with each other.

In 1750 the Chancery Court in London issued a ruling that was made binding and included provisions of many of the earlier decrees. The most important provision was that the northern boundary of Maryland would be 15 miles south of the southernmost part of Philadelphia. A commission made up of people from the colonies was selected to draw up the boundaries.

The commission knew it needed to do a proper survey, and at first local surveyors were hired. Unfortunately they lacked the technical skills needed, and their instruments were not as precise as was required. It also became evident that the surveyors must be viewed as independent, or the attacks on them would continue. The solution was to hire Charles Mason and Jeremiah Dixon in 1763. They had achieved renown by observing the Transit of Venus in 1761 in Southern Africa. In this rare event Venus passes between the sun and the earth, enabling scientists to determine the distance from the earth to the sun.

The surveyors faced many potential problems. One problem was armed conflict between Native Americans and colonists in the western part of Pennsylvania and Maryland. The alliance of tribes under Chief Pontiac was attacking settlers and forts in the area.

Another problem was where to start the survey line 15 miles south of Philadelphia. If they traveled due south from the southernmost point, they would have to go across the Delaware River and start in New Jersey. They decided to head due west instead and stopped at John Harlan’s farm 31 miles west of Philadelphia. That spot is marked today by what is called the Stargazers Stone in a front yard on Stargazers Road in Embreeville. The stone was named for the many astronomical observations made by the surveyors to determine their exact location. Once they were sure they were exactly west of the southernmost point of Philadelphia, they began to work their way south in January and February 1764.

First, ax men were hired to cut trees in an eight-yard wide path to accommodate the survey. Then Mason and Dixon started their measurements. After two and a half weeks they came to a field owned by Alexander Bryan, 15 miles south of the turning point on Harlan's farm. An observation platform was built on the spot from which celestial readings were made to confirm that they had measured accurately.

When they were certain they had the right spot they placed a stout oak post in the ground and painted it white with the word "west" on its western face. This was to be called the “Post Mark’d West.” It was from this point, 15 miles south and 31 miles west of Philadelphia, that they would begin their survey. This became a constant point of reference that they would use as they moved westward to establish the boundary between the battling colonies of Pennsylvania and Maryland.

This is how Mason described the location of this significant point in his journal:

The point 15 miles South of the Southernmost Point of the City of Philadelphia is situated in Mill Creek Hundred in the County of Newcastle, in a Plantation belonging to Mr. Alexander Bryan. The Middle of the Front of Mr. Bryan’s House, bears from the point 37’ 52’’ Northwesterly distant 23.38 chains (each chain 22 yards). It is close by the East side of a small Run, the Head of which is due North distant 5.00 chains. From the Point to the Middle of a small rivulet called Muddy Run, on a due South course is 7.15 chains.

During their time in Delaware in March and April of 1764 and again in 1765 the surveyors stayed at a small inn in Newark, two miles south of Bryan’s field. The history of the Deer Park Tavern in Newark suggests that it was an inn situated on the same property, known as St. Patrick’s Tavern. An account of that time said that while at the Inn they kept a trained bear and consumed large amounts of peach and apricot brandy. The weather of that time was not very welcoming. In 1764 they had heavy rain for their visit. In 1765 the weather was very cold with much rain, sleet, and snow. On March 24, 1765, the snow in Bryan’s field was measured at 2 feet 9 inches deep.

Before starting westward, they had to first determine the middle point of the (Delmarva) peninsula so they would know the exact location of Maryland’s eastern boundary. This meant traveling to southern Delaware and, once determining the exact middle, working their way north until they met the 12 mile arc from the city of New Castle. They worked on this from June to November 1764. They then went back to Harlan’s farm for the winter.

On April 4, 1765, they were ready to begin moving westward starting at the “Post Mark’d” West” on Bryan’s field and soon entered Maryland. At that time Maryland was much more of a wilderness area than Delaware. Now they began living in tents and cooking by campfire. Wild game supplemented their diet. In the forests were wolves, bear, elk, and deer.

The survey crew consisted of a steward, tent keepers, cooks, ax men, chainmen, and laborers. They had 2 wagons and 8 draft horses. As this large group moved west they no longer faced the hostility that had greeted previous surveyors. One reason was that Mason and Dixon were very well-known astronomers and were viewed as independent. Their 40-member group constituted a formidable presence in the sparsely populated area. The locals also benefited from the readily available logs for buildings and firewood as the ax men cleared an 8-yard wide swath through the wilderness.

They had to stop on October 9, 1767, about 30 miles short of the western boundary of Pennsylvania because the Native Americans indicated that the limits of intrusion in their territory had been reached.

Mason and Dixon’s skills as surveyors have stood the test of time. Even with more modern surveying techniques, there has been found to be only a very slight shift of the line they measured.

Today the important “Post Mark’d West” is celebrated by a cement marker donated in 1952 by Mr. S. Hallock duPont, owner of the property at that time. It is easily accessible from a short side trail off Bryan’s Field Trail in the Possum Hill section of the park. The other Mason and Dixon monument near White Clay Creek State Park is the Tri-State Marker (the northeast corner of Maryland) that is located off Rt. 896 north of Newark on private property.