“A Plan of the Boundary Lines…between the Provinces of Maryland and Pennsylvania,” 1768. Charles Mason (1728–1786) and Jeremiah Dixon (1733–1779),

Mason Dixon C1311_MS Map_23From 1763 to 1768, Charles Mason and Jeremiah Dixon surveyed the boundary lines between Pennsylvania and Maryland, and between Maryland and Delaware. Drawn and signed by both men, this map shows the eastern section of the boundary. The first official use of the term “Mason’s and Dixon’s Line” appeared over fifty years later in the Missouri Compromise of 1820, which decreed that slavery would be prohibited above the line and allowed below it. Gift of Mr. and Mrs. John H. Doran, in memory of their son, Joseph I. Doran II, Class of 1935. Manuscript Maps Collection, Manuscripts Division.

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