Ma·son-Dix·on Line (māsən-dĭksən)
A line marking the boundary between the colonies of Pennsylvania and Maryland, established between 1763 and 1767 by the British surveyors Charles Mason (1730-1787) and Jeremiah Dixon (1733-1779). It was regarded as the division between free and slave states before the Civil War.
(click for a larger image)Mason-Dixon Line
The original line extended from the southeast corner of the colony of Pennsylvania 233 miles west and 82 miles south.
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2020 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
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