PHILADELPHIA — If Todd Babcock had his way, the Mason-Dixon Line would be known as the technological marvel that kept Philadelphia in Pennsylvania, not as flawed shorthand for the Civil War divide between North and South.
The land survey that settled a border feud between Pennsylvania and Maryland predates the Civil War by a century. It started at a house in Philadelphia whose location was only recently confirmed by a group of college students paging through centuries-old property records.
The research led state officials to approve a historical marker for the site last month. Babcock and other members of the volunteer Mason and Dixon Line Preservation Partnership plan to erect it for the line's 250th anniversary in 2013.
"Charles Mason and Jeremiah Dixon's accomplishment has been buried in the fog of bad history and I hope to change that," said Babcock, 46, a professional surveyor from Fleetwood, Pa.
Babcock's efforts come as the U.S. marks the 150th anniversary of the Civil War. "Mason-Dixon" has become synonymous with the North-South line — Maryland allowed slaves, Pennsylvania did not — even though Maryland was a Union state.
The boundary had nothing to do with that. Begun in 1763 and lasting four grueling years, the demarcation involved celestial navigation of more than 300 miles of wilderness while transporting a delicate 6-foot-long telescope, food and other supplies by horseback, said Babcock.
Mason and Dixon were British surveyors hired to settle a dispute between two powerful families: the Penns of Pennsylvania and the Calverts of Maryland. The Calverts claimed land extending north to Philadelphia, while the Penns asserted ownership south into Maryland.
Mason and Dixon were charged with marking the border at a latitude 15 miles south of Philadelphia. But what was the city's southernmost point?
Municipal records from that time indicate only that the point was the northern wall of a house owned by Joseph Huddle. Babcock said researchers long surmised the house was near Front and South streets — now an area with funky shops and restaurants — but no one had found a deed with Huddle's name and a location.
Enter Janine Black. The Philadelphia resident had contacted Babcock's group a couple of years ago after reading that Huddle's house supposedly stood a few blocks from her home. In a city teeming with historical markers, she asked, why was there none for this house?
Babcock told her of the missing documentation. So Black, who teaches business at Penn State-Abington, obtained a small grant for three interested students to painstakingly comb through city archives. For months, they pored over yellowed property records, difficult-to-read handwriting and numerous spelling variations.
Last May, student Indiah Fortune found a deed from 1754 with Huddle's name and a site matching the description in city records. Four months later, student Amanda Veloz found an insurance card confirming the location at the corner of Water and Cedar (now South) streets.
"It took a while to finally hit me that now I'm a part of history," said Fortune, currently a 20-year-old junior at Penn State's main campus in State College.
Yet the site, which is about two blocks from the purported location at Front and South, no longer exists. It was obliterated decades ago by Interstate 95.
Still, Babcock and Jim Shomper, another member of the preservation partnership, spent a morning last month poring over surveyors' maps to calculate where the house would have been. A pedestrian bridge extending South Street over I-95 allowed them to mark the approximate location above the northbound lanes.
They also determined the site of a nearby observatory where Mason and Dixon made their first celestial calculations. Shomper, a longtime professional surveyor, believes that data can also help determine the location of a long-lost observatory behind Independence Hall.
Shomper said research indicates the Declaration of Independence was first read to the public from the observatory on July 8, 1776. Jane Cowley, a spokeswoman for Independence National Historical Park, could not confirm the reading but said the observatory's foundations are believed to be under Independence Square.
Confirming its location "would be of great interest," Cowley said.
After Mason and Dixon gauged the southernmost point in Philadelphia, they traveled due west to Embreeville, Pa., to put themselves directly above the disputed Delmarva Peninsula.
They matched the Philadelphia latitude and traveled 15 miles due south, putting the first marker of the Mason-Dixon Line in what is now White Clay Creek State Park in Newark, Del. From there, they marked each mile of the border south into the Delmarva and then west toward Pittsburgh.
Nearly all 230 original markers along the Pennsylvania/Maryland line remain in place, Babcock said. GPS calculations show the stones vary a few hundred feet north or south of the target latitude, he said.
"With all of our modern technology, modes of communication and ease of transportation, this would be a daunting task to complete today," Babcock said. "The logistics of the undertaking of this project are incredible."
In 2013, Babcock's group plans to place the historical marker near the South Street pedestrian bridge.
They also plan a ceremony at Mason's grave, which is currently unmarked in the same Philadelphia cemetery where Benjamin Franklin is buried. They hope to mark it with one of the original stones from the Mason-Dixon Line.