“There was no way they could win,” Childers told me. “There was nothing on their side that could prove the line was where they said it was.”

Borders in North Carolina, like in much of the United States, are disappearing. Lines drawn centuries ago weren’t just marked on maps—they were physical demarcations, denoted by ditches, fences, or markings on trees. But ditches can be filled, fences fall apart, and trees are cut down, and over time these visible landmarks have vanished. In their absence, some cities and counties have become unsure about who should be paying their taxes, attending their schools, and using their services.

“If someone is having a heart attack, who are you going to call?” said Brian Carson, a geographic-information-system specialist with the Orange County planning office. “You don’t want there to be any uncertainty.”

But in North Carolina, there’s plenty of uncertainty. To fix it, Gary Thompson, the head of the state’s geodetic-survey office, also acts as its chief boundary hunter. His work is a study in opposites, a combination of centuries-old maps and cutting-edge technology that allows him to replace long-gone markers like “the dead pine tree” with exact spatial coordinates.

“Two hundred years from now,” Thompson said, “they won’t have to worry about finding that tree.”

* * *

In 1950, a state archivist named David Corbitt published Formation of North Carolina Counties: 1663-1943, an exhaustive history of the formation of the state’s 100 counties, stretching back to the first English colonists in the area. According to the records unearthed by Corbitt, Alamance County was to be carved out of the much larger Orange County in 1849, and each county hired a surveyor to mark the agreed-upon boundary. But Orange County’s representative failed to show up, a frequent occurrence in a job characterized by low pay and sometimes-treacherous work (if the snakes and mosquitos didn’t get to surveyors, unhappy landowners sometimes would).

When the two men finally hit the ground in 1851, accompanied by a team of lumberjacks that would clear their path, they used compasses and long chains known as Gunter’s chains to mark a line “beginning at a gum sapling on the Caswell [county] line and running due South to a birch bush on the bank of the Haw river.”

Presumably everyone knew where that sapling and bush were in the day—and even if they didn’t, land was so plentiful that absolute accuracy was not required. But by the late 20th century, the county line’s exact trajectory was subject to interpretation.

“Our county had one definition of where the boundary was, Alamance had another, and the USGS had a third,” said Carson.

Discrepancies like this one hadn’t been a problem when most of the state was still rural, and tax assessors in adjoining jurisdictions could swap parcels to work out differences. But by the late 20th century, increasing development near these grey zones was stirring unease in county courthouses.