We Sent a Cartographer to the Sale of One of America's Most Famous Maps
As the original survey map of the Mason-Dixon Line heads to the auction block, National Geographic senior cartographer Scott Zillmer explains what everyone gets wrong about it.
On a spring day in 1982, a never-before-sold piece went under the hammer at Christie's auction house in New York City. In a moment he later said left him breathless, Malcolm Forbes, Jr., the president of Forbes magazine, raised his paddle and won the hand-drawn survey of the Mason-Dixon Line for $360,000—the most ever spent on an American map at the time. The sale shocked bidders: As the price climbed to more than 20 times its estimated sale price, it also managed to overshadow a rare copy of the Declaration of Independence (which fetched $285,000). The losing bidder for the Mason-Dixon map was the Library of Congress.
Forbes ended up with an unusual-looking relic: six sheets of paper conjoined into a manuscript just six and a half inches tall and over six feet long. It’s believed to be the only original copy of the western section of the Mason Dixon survey—the most famous border in America.
More than 40 years later, that same map has now sold for $1,187,500 to an anonymous buyer, according to Brunk Auctions in North Carolina. The bidding started at $400,000, a sale price that doubled within mere minutes.
Today, the Mason-Dixon Line is synonymous with a divided America, and its darkest era. But it was originally created to settle a long-running dispute between two families in the newfound American colonies. In 1681, King Charles II of England gave William Penn a charter to travel to America and settle the land between New York and Maryland, erasing a debt he owed Penn’s late father. But the creation of the Pennsylvania colony enraged Charles Calvert, or Lord Baltimore, the proprietor of neighboring Maryland. The boundary, he said, overlapped with his colony’s northern border. Undeterred, Penn continued to build Philadelphia, which sat on land Calvert claimed. In subsequent decades, a number of high-profile clashes broke out as surveyors failed to reconcile the conflicting territorial promises.
In September 1763, two renowned British astronomers named Charles Mason and Jeremiah Dixon set sail for America to tackle the growing conflict over the boundary. The pair expected to turn the job around in one month. Instead, they launched what would become a four-year expedition from Philadelphia alongside a team of Haudenosaunee guides.
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In October 1767, 233 miles later, they reached as far west as they could go: At Dunkard Creek in what’s now West Virginia, the Haudenosaunee guides refused to proceed due to hostilities with the Delaware tribe. The team decided to turn back and write up their findings, which established borders for Pennsylvania, Maryland, Delaware, and modern-day West Virginia. Penn’s descendants must have been pleased: Pennsylvania kept most of its claimed land, including chunks of Maryland and Virginia. It would take another 17 years for others to finish surveying the remaining 36 miles of the northern border of West Virginia.
In the meantime, a country deeply divided by slavery began to use the Mason-Dixon Line as a shorthand to informally delineate North and South—or non-slaveholding and slave-holding states—in the lead-up to the Civil War. Although that characterization has stuck around until today, it has never been quite accurate: In reality, slavery was prohibited above the 36º 30' latitude line along the southern boundary of Missouri (although for complicated reasons it remained legal within Missouri). Meanwhile Maryland, which sat south of the line, was put in an awkward position as it remained loyal to the Union in the North.
The accuracy of the Mason-Dixon Line itself has held up each time it has been resurveyed, once in the 1800s and twice in the 1900s. Yet for years, one of the original sketches of the pioneering surveys made by Mason and Dixon—that of the western boundary—was thought lost.
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In fact, the hand-drawn survey remained in the possession of descendants of Benjamin Chew, the chief justice of Pennsylvania who had helped draft Mason and Dixon’s final report. Nearly two centuries later, in the 1960s, a historian was examining the document when he realized it was not an engraving of the western map, as previously believed—it was the only surviving original copy. (The eastern boundary map of Delaware is now held at Princeton University.)
Nineteen years later the western map went to auction, and into the hands of Malcolm Forbes Jr., in 1982. In 2002, it sold again, for $556,000. Since then, it has been painstakingly restored by experts at Colonial Williamsburg. Replacing the old linen backing with Japanese paper alone took more than 200 hours, according to Brunk auction house.
''No, I wouldn't call it a bargain,” Malcolm Forbes Jr. told the New York Times immediately after his winning bid was recorded. “But to anyone who knows American history and the map's importance among the events that led to the Civil War, it is priceless.''
