To be a Sheldon Cooper, the Mason-Dixon line is not a line, but is rather a series of lines. You can even argue that they should not be called lines since they are really arcs, due to the curvature of the Earth. So how does The Mason-Dixon Arcs sound? Well we wont go that deep but...
The most famous Mason-Dixon line is a line of Latitude: 39°43' north. The least known Mason-Dixon line is the "North Line" and it is a line of longitude that falls along the 75° West. Finally the Tangent line that is the main division between Maryland and Delaware does not dived the North and South, but rather divided East and West.
The Mason-Dixon Line or rather the Chuck-Jerry Line is a cultural phenomenon in the USA. Originally is was a border commission by King George III to settle a dispute between two slave holding colonies: Pennsylvania and Maryland. Nonetheless, the Mason-Dixon Line has transformed into an iconic divide between the North and South.
Some historians just use the upper line of latitude at 39° 43' North as the Mason-Dixon Line. Others extend it as the divide between free and slave territories, such that the northern borders of Kentucky and Missouri are the 'Mason-Dixon Line.' Finally some just follow the actual three survey lines charted by Charles and Jeremiah. Who is right? Well in today's understanding of a multilateral view of history and things, they are all right depending on your point of view, sorta' like a quantum string theory view of things.
Based upon these various interpretations, two flags have already been created. One for the line at latitude at 39° 43' North, which you can read about
it here. Another that follows the divide between slave and free soil as it was in 1861. And finally here is flag that follows the official survey line from 1763 to 1767 that divides Maryland and Delaware by East-to-West as well as Pennsylvania and Maryland by North-to-South.
The design of the flag is based upon the County Flags of the surveyors who spelled out the Mason-Dixon Line. Mr. Mason was born in southern England, Gloucestershire County, on April 1728. Mr. Dixon was born in northern England, Durham County, in July 27, 1733. Gloucestershire County's flag has a centered blue cross, outlined with light beige, and green filling up the outer quarters. Durham County's flag is horizontal bicolour of yellow on top and blue underneath with a counter coloured cross in the center.
The Dixon & Mason Survey Flag is based upon the pattern of the Maryland Flag and modified versions of the Gloucestershire and Durham County flags. A new colour added is white to the Survey Line Flag of Dixon & Mason for the outline of Gloucestershire's component and for Durham the central circle in the cross has a white disc.
This flag directly honors Charles and Jerry for setting up the Mason-Dixon Line. It should only be flown along the lines where the stones are marked off between Maryland with Pennsylvania/Delaware, where the famous M-P Milestones can be found. Thus this flag can only be flown across the Tangent Line, North Line and along 39°43' until the last marker in western Pennsylvania/West Virginia.
As for the other two Mason-Dixon Flags: The 39°43' north Flag should only be flown at that latitude across the US; the Penn-Calvert flag follows the divide between free and slave soil as it was in 1861 from Marcus Hook, Pennsylvania to Poston, Arizona. But note that all three flags overlap Pennsylvania-Maryland border.
It was quite a project when these two mathematically educated surveyors arrived in Philadelphia on Novermber 15, 1763. They finished their survey in 1767.