"boundary line"
by cm

Mason-Dixon Line
Public DomainMason-Dixon Line
The Mason-Dixon line separates the U.S. states (then colonies) of Pennsylvania and Maryland, as well as West Virginia and Delaware.   It is marked by boundary stones at every mile.   Surveyed between 1763 and 1767 to resolve a border dispute (known as Cresap’s War), it has come to symbolize the divide between the northern and southern states of the USA.