The surveyors Charles Mason and Jeremiah Dixon established the boundary
line in 1767, which was to bear their names, resolving a dispute of nearly
ninety years between the Penns and the Baltimores. The boundary, 244 miles in
length, is printed on two sheets, the eastern line on a single copperplate, the
western line, because of its length, divided into three parts, one engraved
under the other. This copy belonged to Benjamin Chew (1722-1810), a member of
the Boundary Commission established in 1750 by the English High Court.