There have been a number of state boundary corrections in the last few decades. Keep in mind, most boundaries were mapped with the old rod and chain method of surveying and the GPS wasn't even something that could be comprehended yet. Even the US border isn't perfect. The town of Derby Line, Vermont is separated by the US/Canada border and even has its library split by an international boundary. Cool! "Fort Blunder" in New York state was build in Canada due to surveying errors. Even the glorious four corners monument is just over 1,800 feet from where it would be if placed by modern mapping/surveying methods. But the courts determined that the location of the monument is the official spot, right or wrong, so a couple of the states just aren't as right angled as they thought they were in that location. Brian Unger's show How the State Got Their Shapes covers a lot of these really cool topics.
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