The default response these days to situations like this is usually conflict, which can be costly. The legal bill for South Carolina’s defense against Georgia, for example, topped $10 million, and so traumatized South Carolina officials that they looked for a peaceful way to find the missing border with North Carolina.

In 1993 the two states’ mapping agencies pledged to cooperate, harnessing geospatial technology to old-fashioned detective work. In one border segment near Charlotte, they unearthed colonial-era property maps that had used the boundary trees as tract corners and overlaid Geographic Information System data — mapping technology accurate within inches — to calculate where the trees once stood.

In another segment, researchers found a stone boundary monument that had been set as part of a 1928 resurvey, except it now stood near a tee on a golf course. Officials at the course had moved it years before so duffers could brag about their two-state tee shot. Using the original 1928 maps, advanced mathematics and some informed guesswork, the joint survey teams navigated to the exact spot where the monument had been uprooted, and even found its broken-off base.

By 2013, the entire 334-mile boundary had been relocated and re-marked. Unfortunately, it was not always where people had thought it was. Some residents living near the boundary discovered that their homes were in fact in a different state. A North Carolina doctor discovered that the room in his home where he sometimes saw patients was in fact in South Carolina, and worried he would have to get a South Carolina medical license.

Fortunately, the two states had seen this coming, and the Joint Boundary Commission they formed to oversee the surveying began to catalog potential negative impacts. The commission sent letters and aerial photos to 173 landowners warning that their lives — and sometimes their addresses — could change, and asked for comments. Those comments are being used to shape legislation that should solve most of the resulting problems.

But an obvious fix is not in sight for Lewis Efird, who bought a gas station just south of what he thought was the state line in the early 1990s to take advantage of South Carolina’s significantly lower gas tax, as well as the ability to sell beer and fireworks. Unfortunately, the survey work showed conclusively that his pumps were in a part of North Carolina where gas is more expensive, beer sales are not allowed and fireworks are illegal. As he told commissioners in a public meeting, “Our business is going to be destroyed.”