Mason-Dixon Survey

Mason-Dixon Survey is a Pennsylvania historical marker in Philadelphia, Philadelphia County, dedicated 2013.

Philadelphia County · dedicated 2013 · Front & South Sts., Philadelphia

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Here, in 1763, the southernmost point of Philadelphia was determined as the starting point for the survey of one of the most important borders in the nation. Charles Mason and Jeremiah Dixon took scientific measurements of a degree of latitude, elevating professional surveying standards. The survey ended a land dispute begun by William Penn and Lord Baltimore. Western Pa. Indian wars and severe weather delayed completion of the line until 1768.

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under a mile from where William Gabby lived in the 1760s

what this marker records spans 1777 to 1789, overlapping William Gabby's years here

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Marker data: Pennsylvania Historical and Museum Commission via data.pa.gov

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