Mason and Dixon Determined Starting Point for Boundary Survey, December 30, 1763

The dispute over the boundary of the province on the south began with the acquisition of the charter and continued through the life of William Penn and his descendants, until almost the end of Proprietary Government in Pennsylvania.

Charles Calvert, the fifth Lord Baltimore, drew an agreement, defining the boundaries between Maryland and Delaware and Maryland and Pennsylvania. On May 10, 1732, John and Thomas Penn agreed to this and signed the instrument. John Penn and Lord Baltimore then came to America, and, Baltimore changed his mind and caused every possible delay in having a survey made of this disputed line.

Commissioners had been appointed by both governments and they did nothing but wrangle for the eighteen months allowed in the agreement, and Baltimore believed this made it of no effect.

The Penn family won in court and the conduct of Baltimore was censured.

Frederick, the sixth Lord Baltimore, declined to be bound by any act of his predecessors, and again many years were wasted.

In 1760 a new agreement was made which was practically identical with the one of 1732. Commissioners on the part of Pennsylvania were the Governor, James Hamilton, Richard Peters, Reverend Dr. Ewing, William Allen, William Coleman, Thomas Willing, Benjamin Clew, and Edward Shippen, Jr., a selection which assured good and faithful performance.

The first three years were spent by the surveyors employed in marking the lines of Delaware. The circle around New Castle was drawn by David Rittenhouse, and added much to his reputation.

This work proceeded too slowly and on August 4, 1763, Thomas and Richard Penn, and Frederick, Lord Baltimore, then being together in London, agreed with Charles Mason and Jeremiah Dixon, two well known English astronomers, “to mark, run out, settle, fix, and determine all such parts of the circle, marks, lines, and boundaries, as were mentioned in the several articles or commissions, and were not yet completed.”

Mason and Dixon arrived in Philadelphia, November 15, 1763, and forthwith engaged in work.

They began their survey by ascertaining the latitudelatitude of the southernmost part of the City of Philadelphia, which they agreed was the north wall of the house then occupied by Thomas Plumstead and Joseph 920Huddle, on the south side of Cedar Street. They determined it was 39° 56' 37.4”. This was ascertained December 30, 1763, and the actual survey of the boundary line properly began on this date.

During January and February, 1764, they measured thirty-one miles westward of the city to the forks of the Brandywine, where they planted a quartzose stone, six miles west of the meridian of the court house in West Chester.

With this stone as a fixed point they determined the point from which they should start to run the horizontal line of five degrees longitude to fix the southern boundary. This was of course the northeast corner of the State of Maryland.

From this point they extended the line 230 miles, eighteen chains, and twenty-one links, or 244 miles, thirty-eight chains, and thirty-six links, from the Delaware River. This was done during 1766 and 1767.

The Indians could not understand the object of an exploring expedition that spent every clear night gazing at the stars through big guns, and they soon stopped their progress. The Penns used their influence with the Indians and the work proceeded.

The western extremity of Maryland was reached and passed, and the astronomers were encamped on the banks of the Monongahela, when the Indians again interposed. Their attitude was so threatening that many of the servants and workmen of the expedition deserted. But the great delight and satisfaction of running an astronomical line through primeval forests raised Mason and Dixon above all fears, and they pressed on to the Warrior Branch of the great Catawba Indian trail.

This was on the borders of a stream called Dunkard Creek, about the middle point on the southern boundary line of the present Green County. Here the Indians took such a menacing stand that Mason and Dixon were obliged to return, and their Dunkard Creek trail, or Warrior trail, remained the terminus of their line for many years.

This Mason and Dixon’s line was a great achievement in that day, and a new thing in science. These two modest but skillful men had made themselves immortal. Their line was not marked by river, creek or even mountain range, it was an imaginary one. At every fifth mile a stone was set up marked on the northern side with the arms of the Penns and on the southern side with the arms of Baltimore, each intermediate mile was marked with stones having P. on the one side and M. on the opposite side.

This line, fixed after nearly a hundred years of conflict, is more unalterable than if nature had originally made it. It became the boundary line between the great sides of the slavery question, and divided the armies of the North and South in the great Civil War.

The interference of the Indians having arrested further work, Messrs. Mason and Dixon returned to Philadelphia, where they reported 921to the commissioner, and on December 26, 1767, received an honorable discharge.

There were many minor disturbances occasioned by this line, and the actions of the rough border population were slow to become satisfied. A surveyor’s transit or astronomy was not enough to determine the limits of their civil pride. These people had grown accustomed to the temporary lines which had been run about 1740, which was about one-quarter of a mile above the true one, and they became as much excited over that narrow strip as they had been when they hoped to penetrate miles into Pennsylvania.

The government of Pennsylvania determined to acquire its rightful jurisdiction and in 1774, a proclamation was issued, which has generally been considered the final act in the boundary controversy.

The residue of the southern boundary, a little less than twenty-two miles, was run in 1782 by Robert Andrews, Andrew Ellicott, John Ewing, David Rittenhouse, and John Hutchins, and completed and permanently marked in 1784.