Yohogania County, Virginia

The problem arose through the complex and conflicting manner of granting territory and defining boundaries during the Colonial period.

The disputes over which colony had authority over the area led to overlapping land grants to settlers and battles between Virginians and Pennsylvanians in the period 1774–1775.

Similar conflicts between Maryland and Pennsylvania had been resolved earlier, by 1767, through the work of two men chosen by Cecil Calvert, brother of Charles Calvert, 5th Baron Baltimore, proprietor of Maryland, and Thomas Penn and his brother Richard, sons of William Penn and proprietors of Pennsylvania.

Astronomer Charles Mason, an acquaintance of Benjamin Franklin, and surveyor Jeremiah Dixon came from England to do this work.

However, their authority extended west only as far as western Maryland, and did not resolve border conflicts between Virginia and Pennsylvania.

On December 27, 1779, a resolution by the Second Continental Congress recommended to the two now-states of Virginia and Pennsylvania that, rather than continue to quarrel with each other as well as fighting the British, they should reach an agreement on the border situation.

On November 4, 1782, Colonel Joseph Neville, representing Virginia, and Alexander McClean of Pennsylvania marked a temporary line.

A final, permanent survey was performed by Neville and Andrew Ellicott, a Marylander representing Virginia.

In 1786 the line was continued to Lake Erie, marking the boundary between Pennsylvania and the portion of the Northwest Territory that in 1803 became the state of Ohio.