After this, the government of Maryland petitioned King George to intervene and settle the boundary dispute once and for all. Then in 1736, according to the National Park Service, he was accused of murder by the Pennsylvanians and captured after his house was set on fire. In time, the trading post he built became an important Maryland outpost. He did so and began doing business with the Pennsylvania Dutch, claiming the taxes they paid for the government of Maryland. Maryland responded by getting Thomas Cresap, a man who had been a land agent for the Calvert family of Maryland, to build a settlement by the Susquehanna River. “Despite the Crown’s mandate, Pennsylvania created Lancaster County, clearly extending south of the border as claimed by Maryland,” writes trivia expert Dan Lewis. In 1724, the British crown told them to work it out politely. The two colonies began arguing about where the border actually was. Pennsylvania's charter described its boundaries in complicated (by modern standards) terms, saying that its southern border should be 'a Circle drawne at twelve miles distance from New Castle Northward and Westward unto the beginning of the fortieth degree of Northern Latitude, and then by a streight Line Westward to the Limitt of Longitude above-mentioned.' However, whoever surveyed the colony made a serious geographical error, since the 40th Parallel was north of Philadelphia-which would have put the growing city in Maryland, not Pennsylvania. This shows the strip of land that was being fought over between Maryland and Pennsylvania. Memory of the conflict was one of the original reasons that the Calvert and Penn families, the founders of Maryland and Pennsylvania, respectively, paid for the Mason-Dixon line to be surveyed.

This little-known border conflict eventually required the British crown to step in and restore peace. It was this competing interest that led to Cresap’s War, also known as the Conjocular War, a bloody eight-year conflict over the city of Philadelphia and surrounding area.

Getting along with neighbors is always a challenge.Ĭolonial Maryland and Pennsylvania had it harder than most: they both had legitimate (to them) claims to a large area of land.

Mason dixon line