Chester County Played a Critical Role for Mason and Dixon

Tracing the Mason-Dixon Line’s uncertain path through Chester County.

With a clever combination of astronomy, mathematics and surveying, intrepid Englishmen Mason and Dixon plotted the boundaries that bear their names: an invisible line hailed as the most widely known in the world, next to the Equator. To this day, few know of Chester County’s indispensable role in the historic mission.

An early rendering of the Mason-Dixon Line.Their task was enormous. Imagine plowing through uncharted territories with only dodgy maps to confirm your bearings. They calculated a narrow swath through the wilderness in relation to the stars by utilizing a highly developed 6-foot brass telescope, as the sounds of a legion of axes echoed across the timberland. With a crew of upwards of 115 men, Englishmen Charles Mason and Jeremiah Dixon trudged through flooded fields, confronted poisonous snakes and wild animals, and observed the night sky through frigid winters and oppressive summers. They also risked their lives on the western frontier, where Colonists and Indians slaughtered each other in the French and Indian War’s aftermath. The two surveyors persevered over five grueling years, measuring more than 230 miles of boundary heading west through Maryland and Pennsylvania.

After their ship docked in Philadelphia in November 1763, Mason and Dixon’s first project was to fix by the stars the southernmost point in Philadelphia. They determined it to be Cedar Street, now Second and South streets.

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A line due south would’ve put them in New Jersey. So, instead, they loaded a small cavalcade of covered wagons with supplies and observation instruments, and rode west to Chester County. On Jan. 14, 1764, they arrived at John Harland’s farm in Embreeville, 6 miles south of West Chester.

Not far from the residence, Mason and Dixon sunk the “Stargazer Stone,” the point from which the surveyors located the Pennsylvania-Maryland border. They’d determined that they were near the same latitude as Philadelphia’s southern limit, 31 miles west. At the time, it was the most accurately measured point in America.

Today, on Route 162, there is no indication of the famous surveyors; a blue-and-gold highway marker was swiped years ago. The Harland House is still there. A two-story stone structure adorned with gray-blue shutters, the historic home dates back to the 1690s. Tolly Roby, a local veterinarian, purchased it in 1983.

“I walked through the front door into this room with the walk-in fireplace, and I fell in love with it,” Roby says. “I started doing research with my brother on the title and began to uncover all this history about the Harland family who lived here until the 1950s. It’s one of the oldest homes in Chester County, so I’ve been not only seriously researching what happened here, but also preserving the house and the Mason-Dixon connection for future generations.”

On a visit last fall, Roby led a tour of the house’s original core. Renovations have transformed some of the home, but the hand-hewn oak beams and floors are original. So is the fireplace.

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Tolly Roby in front of her historic home in Embreeville, where Mason and Dixon set up camp in the winter of 1764. (Photo by Jared Castaldi)Mason, 35, and Dixon, 30, spent the winter of 1764 at Harland’s farm making astronomical observations on clear nights. On cloudy evenings the surveyors often stood in front of a roaring fireplace discussing their endless, complex calculations and swapping stories with the Harland family. Madeira wine and spirits flowed freely. “Mason and Dixon were serious partyers,” says Roby, flashing a grin. “There’s a nearby creek known as Punch Run, and legend has it they made some heavy-duty rum punch over there.”

The guys enjoyed their drink. One of their supply lists called for “120 gals spirits, 40 gals brandy, 80 gals madeira wine.” When nasty weather forced them to suspend the survey, Mason and Dixon returned every winter to the cozy hospitality of the Harland House at the “forks of the Brandywine River.”

Genealogical records talk about a Dina Dixon, who married Michael Harland—and that both families were originally from Durham Count, England. “They might have been shirttail cousins, so that could be why Mason and Dixon wound up here,” says Todd Babcock, a professional surveyor and historian who has traveled the entire Mason-Dixon line. “It also makes sense that they sat next to this fireside and sketched out their final maps, because they had to return to Philadelphia and have the commissioners sign off on them.”

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A short walk away and up a grassy incline, we come to the Stargazer Stone, a shaft of white quartz stone, still where the surveyors placed it 246 years ago. The Chester County Historical Society imbedded it in concrete and built a low, 2-foot wall around it in 1906. “The stone helped them understand the size and shape of the Earth,” Babcock says. “Numerous scientific projects unfolded there. It was critical in establishing the latitude. And through their nightly observations, that stone became a reference point of Mason and Dixon’s entire five-year survey.”

In early March of 1764, the survey party packed up and turned southward after Mason and Dixon ran a line 15 miles due south from Harland’s farm. It was measured with survey chains and levels as a team of axmen cleared the virgin forests. In April, they arrived at a farm field owned by Alexander Bryan in what is now the Possum Hill section of Delaware’s White Clay Creek State Park. They placed an oak post called “Post Mark’d West” at a latitude of 39o 43’ 26.4” N. The original post disappeared, but a granite replacement stone was installed in the 1950s.

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It was a 100-year war, of sorts. An intercolonial family squabble erupted between William Penn and Charles Calvert (Lord Baltimore) in 1681. Both families had been deeded land by British kings, but the deeds overlapped. Since it was unclear who owned what, the landlords had trouble collecting taxes.

The bloody boundary dispute dragged on for three generations as heirs and successors struggled to thrash it out. Finally, in November 1763, Mason and Dixon were hired to establish the boundary lines and lay the milestone markers that still dot the Maryland-Pennsylvania-West Virginia border. They did the same for 83 miles in Delaware.

Mason was an astronomer employed by the Royal Society in Greenwich, England. He spent his time observing the stars and the Moon, and established lunar tables that could determine longitude. Dixon was a surveyor from Cockfield in Durham County, England. The son of a wealthy collier, he was educated by John Bird, a renowned creator of high-precision astronomical instruments.

In 1763, the duo had earned international acclaim for their readings during an astronomical event known as the Transit of Mars. Mason was said to be clinical and reserved, while Dixon was labeled a free spirit. Their American boundary line heading west stands among the greatest scientific achievements of the time as the longest linear survey ever attempted.

Their workforce included axmen, shepherds, instrument and tent carriers, cooks, and even a milkmaid. The largest numbers were axmen and packhorse drivers. Stopping only on Sundays and for an occasional torrential rain, the work was backbreaking. They battled through an unforgiving landscape that, at times, was deadly. Moses McClain, the steward for the survey, noted in his journal that a falling tree killed two of his men.

Though they traveled with Native Americans from the Six Nations as guides, Mason and Dixon were stopped in the western part of Maryland’s Washington County (at 233 miles) as they approached territory occupied by other hostile tribes. It was years before the Mason-Dixon line was run to the Ohio River by other surveyors.

Wagons carried huge blocks of limestone imported from England that were placed at 1-mile intervals. Every fifth marker was known as a cornerstone, which carried the coat of arms of the Penns on one side and the Calverts on the other, pointing out the family’s side. As the terrain got more hilly, the surveyors abandoned the markers, erecting large rock groupings or cairns instead.

Today, those limestone markers and Mason’s journals are the most tangible links to their accomplishments. Babcock, chairman of the Mason and Dixon Line Preservation Partnership, and Dilwyn Knott have led a team of 100 professional surveyors who volunteered to document and preserve the physical condition of the stones along the iconic 233-mile boundary line.

A resident of Fleetwood, Pa., Babcock also hopes to debunk the most enduring myth—that the Mason-Dixon line was the divider between North and South, freedom and slavery, during the Civil War. As it turns out, the line’s origins have nothing to do with slavery.

“It’s always been a line of contention,” says Babcock. “It seems there’s always been a dispute about it. I think, with Maryland being a Southern sympathizer and Pennsylvania a northern state, people of that era latched on to the Mason-Dixon Line—and it’s held through history. Geographically, it really doesn’t make any sense.”

Babcock hopes his two-decade mission inspires people along the line to look after the boundary stones. The team’s goal: to wrap up the venture by the fall of 2013, the 250th anniversary of Mason and Dixon’s arrival in Philadelphia.

“They looked at stars, while today we take readings off satellites orbiting the Earth,” he says. “I’ve gained a greater respect for the hardships they went through. Few at that time could’ve accomplished what they did.”

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