A commissioned officer in the Maryland militia, Major Andrew Ellicott was a highly accomplished surveyor who, along with Pennsylvania's David Rittenhouse, extended the Mason-Dixon line westward to its originally intended terminus at the southwest corner of Pennsylvania in 1784. English surveyors Charles Mason and Jeremiah Dixon had been forced to halt their work at the 244-mile point in 1767 due to the threat of hostile Native Americans. The following year, Ellicott was hired to revisit this survey in order to establish and mark 100 miles of the western boundary of Pennsylvania, a line tha…
