apr 5, 1765 - After completing the portion of the Mason– Dixon line marking the semi-circular boundary between Pennsylvania and Delaware, English surveyors Charles Mason and Jeremiah Dixon begin the two and a half year process of plotting out the 230-mile boundary between Pennsylvania and Maryland along the latitude of 39°43′20″ N
Added to timeline:
Date:
apr 5, 1765
Now
~ 260 years ago