Phil Gingraw points April 1 to a boundary line in St George, Vt. A boundary issue between two Vermont towns that dated to colonial days is on the verge of being settled by using old maps. At issue: the boundary between Shelburne and St. George, which was laid out in 1763.

ST. GEORGE, Vt. — A colonial era boundary dispute between two Vermont towns that were never exactly sure where one ended and the other began is finally going to be settled.

But it was old maps, not GPS or Google Earth, that ultimately found the common ground for the towns of St. George and neighboring Shelburne. The process has pointed up the art of trying to read the minds of the original surveyors and land granters to establish where the lines were drawn.

"It's a matter of 'let's get this defined,"' said Phil Gingraw, chairman of the St. George Select Board. "Two-hundred-and-fifty years ago, people would not really have cared. Today, I think, things have changed a lot, and that's why we need definition."

Vermont itself was a byproduct of a land dispute between the colonies of New Hampshire and New York.

Both issued land charters for the area between the Connecticut River and Lake Champlain. Much of what became Vermont was first surveyed in the 1760s using primitive equipment in near-trackless wilderness.

"Sometimes, the early surveying errors were so spectacular, we've found areas that had never been in any town," said state archivist Gregory Sanford.

It wasn't until the 1980s, for example, that the Vermont Legislature awarded a 380-acre parcel known as Perley's Gore to Montgomery, even though it had existed for more than 200 years without belonging to any town.

These kinds of boundary disputes aren't uncommon:

n During the severe 2008 drought, the state of Georgia tried to reassert its right to its northern boundary on the 35th parallel, authorized by Congress in 1796 when the state of Tennessee was created. The point on the parallel where Georgia, Tennessee and Alabama meet is on the southern bank of the Tennessee River. It turned out the 19th-century surveyor tasked with finding the western end of Georgia's northern boundary was off by just more than a mile, ending Georgia just south of the river. That left Georgia unable to tap into the river and pump much-needed water south into Atlanta.

n The monument where the four corners of Arizona, Utah, New Mexico and Colorado come together is off by 1,807 feet. But the surveying error has become irrelevant, since the states have adopted the accepted location as the only spot in the country where four states meet.

"These (disputes) occur when this exact thing happens," said Curt Sumner, executive director of the American Congress of Surveying and Mapping, in Gaithersburg, Md. "Somebody has reason to question or be questioned about where their property lies."

Solving them is never easy.

"That's part of the puzzle-working, mind-reading part of what surveyors get into," Sumner said.

On Aug. 18, 1763, acting under the auspices of King George, then-New Hampshire Gov. Benning Wentworth granted charters for the towns of Shelburne and St. George.

Neighboring communities, including Vermont's biggest city, Burlington, had already been laid out. So Shelburne and St. George were squeezed in, their maps overlapping. There was an effort to settle the dispute in 1848, but the issue lingered.

In 2007, a couple built a house on the disputed territory and had to ask for building permits in St. George, even though tax maps showed the land to be in Shelburne.

Despite modern mapping techniques, the towns had to use the old maps, look at stone walls and rock piles and survey the area again.

Even then, the towns had to submit to an arbitrator, because the original maps overlapped.

"You can go to the store and for a couple of hundred dollars buy a GPS that will tell you you're within a few feet of a location," Gingraw said. "If you buy an expensive one, you can be within millimeters. That's what people want, a firm definition of where their property is and what's theirs and what's not theirs."

Under the arbitration agreement reached in February, both towns got some land. The house, meanwhile, will be considered part of St. George. Still needed is a final survey that sets the monuments marking the boundaries, which must be approved by the Vermont Legislature.