A Most Historic Line

Boundary disputes were common during the colonial era of our yet future nation. With the laws enacted by Great Britain, colonists were often helpless without royal support from across the Atlantic. Such was the case with the heirs of William Penn, the founder of Pennsylvania, and George Calvert, the First Lord Baltimore, who established the colony of Maryland.     

George Calvert (1578-1632) secured a land grant from King Charles I, the son of James I, in 1625 that became the colony of Maryland. It was a land of many rivers, including the Potomac, and was divided by the Chesapeake Bay. Since George Calvert was the First Lord Baltimore, the main city of his colony, established after his death, was named after his title. His son, Cecilius, took over the colony after his death.¹

William Penn (1644-1718) acquired his colony of Pennsylvania many years after the death of George Calvert. Born in London, William Penn had no title, but his father (also named William Penn) was an admiral in the king’s navy. During the English Civil War, Admiral Penn fought for the king (who lost the war and his head), and gave generously from his funds to support the war effort. Admiral Penn also managed to stay on the good side of the king’s successor, Oliver Cromwell. When Cromwell died and the British people decided they wanted a monarch after all, Charles II, the son of Charles I, ascended to the throne. By then Admiral Penn had also died, leaving his estate to his namesake son. When William Penn became a Quaker and theologian, his conversion was against British law. For a time, he was imprisoned in the Tower of London. The king, anxious to protect Penn from execution, but bound to obey the law, offered Penn some land in America. He offered property in exchange for the debts the monarchy owed to the estate of Admiral Penn. William accepted – resulting in the colony of Pennsylvania.²

When William Penn died in 1718, his sons inherited his lands. The 2^nd Lord Baltimore, who had also died, left his colony to his heirs. Over time, there were land disputes as to where the border existed between Pennsylvania and Maryland. For a time, the village of Fairfield, Pennsylvania was considered part of Maryland. Soon other towns and villages were in dispute.

Thomas Penn and Frederick Calvert decided that a boundary must be set. Because the colonies were still rather rudimentary in the decade before the American Revolution, they applied to Great Britain for someone to map the region with an inarguable border between the two colonies. Charles Mason and Jeremiah Dixon answered the call.³

Charles Mason (1728-1787) was an astronomer by profession. Born in Gloucestershire, England, he excelled in his knowledge of science. He soon made a name for himself in astronomy and worked at the Royal Observatory in Greenwich, under the Royal Astronomer James Bradley. Mason grasped the principles of science, physics, and astronomy so well, that he was sent abroad to chart the transit of the planet Venus. The work took him, and his assistant Jeremiah Dixon (1733-1779), to the Cape of Good Hope in South Africa, and later to the island of Sumatra. Having accomplished that ponderous assignment, they returned in time to learn they were needed in America. Hired by Penn and Calvert, the pair arrived by ship in Philadelphia in November 1763.⁴

The French and Indian War (called the Seven Year’s War by Great Britain) had just ended that same year, although hostilities among the native tribes were still occurring at times. As the two men surveyed the land along the southern extreme of the future state of Pennsylvania, they sometimes had to halt their work due to uprisings among tribal warriors and French trappers. The surveying, carefully chronicled from their astronomical readings, took four years.

Mason and Dixon placed stone markers – fashioned in England and sent over by ship – every five miles. On the south side was etched the name of Pennsylvania (indicating to travelers they were about to enter north into the new colony), with Maryland placed on the north side of the markers, for those heading south to Maryland. Some of these original markers still exist – on roadsides, in fields, and on private properties.⁵

The two astronomers stayed on through 1767 to aid in mapping the Delmarva Peninsula. They then returned to England.⁶

Charles Mason was married with children. Ever the scholar, Mason had befriended Ben Franklin during his time working on the border. Franklin invited him to join the Philosophical Society in Philadelphia. Once Mason’s children reached adulthood, he and his wife made the journey back to Pennsylvania, where Mason was an active member of the society for the rest of his life. He died in Philadelphia in 1787. He is buried in the Christchurch Cemetery in downtown Philadelphia – remarkably not far from the grave of his friend Ben Franklin, who is buried in the same cemetery.⁷

Jeremiah Dixon never married. A Quaker, he returned to England. He died at the age of 46, and was buried in an unmarked grave in a Quaker cemetery outside London.⁸

Within a few decades, the Mason Dixon Line came to be synonymous with the border between free states and slave states. Some historians, in fact, believe that the name Dixie, a popular term (and song) for the South, originated with Jeremiah Dixon’s surname.

The border established by Mason and Dixon soon became prominent in the conflict between free and slave states. Less than a century later, millions in the United States fought a civil war of their own on both sides of that line – the most pivotal being the Battle of Gettysburg, located just ten miles north of Mason’s and Dixon’s work.

The Mason Dixon Line, however, was originally just a border, separating Pennsylvania and Maryland. It was created in an attempt to bring peace to contention caused by heirs who just wanted their land marked correctly. And two astronomers from England did the work, a fastidious and excellent job that remains to this day.

Sources: Appleton, John, ed. Appleton’s Cyclopedia of American Biography. Vol. IV. New York: Appleton & Sons, 1888. Cope, Thomas D. & H.W. Robinson. Charles Mason, Jeremiah Dixon and the Royal Society. Vol. 9, no. 7. London: Notes and Records of the Royal Society of London, 1751. Federer, William J. America’s God and Country. St. Louis, MO: AMERISEARCH Inc., 2000. William Penn File, Adams County Historical Society (hereafter ACHS). Appleton’s Cyclopedia is available for view on Ancestry.com.

End Notes: 

1. Federer, pp. 34-35. 

2. William Penn File, ACHS. 

3. Appleton, p. 240. 

4. Cope, p. 75. 

5. Ibid. 

6. Appleton, p. 240. 

7. Ibid. 

8. Cope, p. 75. It is possible that Jeremiah Dixon is buried in the same cemetery as William Penn, in the village of Jordans, located between London and Oxford.

Author’s Note: In 2008, during a visit to the Tower of London, I asked one of the beefeater guards about William Penn. He showed me the house on the grounds where he was kept (they trusted him that he would not try to escape), and then told me that if Penn had not accepted the land in America, he would have been executed for being a Quaker. Penn certainly made the right choice.