Mason and Dixon draw a line, dividing the colonies

On October 18, 1767, the Mason-Dixon line, the boundary between Maryland and Pennsylvania, was agreed upon. An excerpt from the article:

"On October 18, 1767, Charles Mason and Jeremiah Dixon complete their survey of the boundary between the colonies of Pennsylvania and Maryland as well as areas that would eventually become the states of Delaware and West Virginia. The Penn and Calvert families had hired Mason and Dixon, English surveyors, to settle their dispute over the boundary between their two proprietary colonies, Pennsylvania and Maryland.

In 1760, tired of border violence between the colonies’ settlers, the British crown demanded that the parties involved hold to an agreement reached in 1732. As part of Maryland and Pennsylvania’s adherence to this royal command, Mason and Dixon were asked to determine the exact whereabouts of the boundary between the two colonies. Though both colonies claimed the area between the 39th and 40th parallel, what is now referred to as the Mason-Dixon line finally settled the boundary at a northern latitude of 39 degrees and 43 minutes. The line was marked using stones, with Pennsylvania’s crest on one side and Maryland’s on the other.

When Mason and Dixon began their endeavor in 1763, colonists were protesting the Proclamation of 1763, which was intended to prevent colonists from settling beyond the Appalachians and angering Native Americans. As the Britons concluded their survey in 1767, the colonies were engaged in a dispute with the Parliament over the Townshend Acts, which were designed to raise revenue for the empire by taxing common imports including tea."