East of this point is mile stone 46 on the line marked by English surveyors and astronomers Charles Mason and Jeremiah Dixon. From 1763-1768 Mason and Dixon used innovative methods to settle a boundary dispute between the colonial proprietors. Each mile of line was set with carved stones brought from England. The Mason and Dixon line defined the border of Pennsylvania, Maryland and Delaware, and was part of the boundary separating free and slave-holding states before the Civil War.