The New Student's Reference Work/Mason and Dixon's Line
Ma'son and Dix'on's Line, often thought to be a line dividing the slaveholding states from free states. In fact, it ran for over a third of its length between two slave-states, Maryland and Delaware. It was run by two English surveyors, Charles Mason and Jeremiah Dixon, during 1764-67, and determines the boundary between Maryland and Pennsylvania and between Maryland and Delaware. Milestones were set up and each five miles marked by a larger stone, on which were cut the arms of William Penn and Lord Baltimore. The work was so well-done that when, in 1849, it was gone over again no mistake of any account was found. The line does roughly divide the north from the south, and is popularly used to distinguish the two sections of the country.