Steve Dansky, age 10, of Philadephia Pa., for his question:

How did the Mason Dixon line come to be?

The famous line is named for Charles Mason and Jeremiah Dixon, the two men who began to mark it on the map. The first section was surveyed 200 years ago to mark the boundary between Pennsylvania and Maryland. Later the Mason Dixon line was Extended to the Mississippi River and beyond.

Andy's readers often wonder how the jig saw boundaries of our states were settled. One of these tricky problems was solved by the Mason Dixon line. Early in the 1700s there were boundary disputes between Maryland and Pennsylvania. Both claimed a strip of land about 40 miles wide. This disputed land was between parallels 39 and 40. Latitudes are parallel lines that run East and west around the globe.

The two young colonies agreed to settle the matter with a boundary to be charted by trained surveyors. In 1760 they began to pace out the exact line, but the work was very slow. They sent for two expert surveyors from England., and in 1763 Charles Mason and Jeremiah Dixon began to mark the boundary between Maryland and Pennsylvania. In four years they surveyed a straight line westward from Chesapeake Bay, plus the western corner of the border. In 1767 the survey was halted by Indians.

Every few Miles stone markers were placed along the carefully surveyed line. The north side of Each marker faced Pennsylvania and bore a carving of William Penn. The south side faced Maryland and bore a carving of the colony's founder, Lord Baltimore. Some of these still mark the Mason and Dixon boundary line between these states.  

Later the western end of the old survey line was continued southwest along the winding Ohio river. It separates Ohio, Indiana, Illinois and Missouri from their southern neighbors of west Virginia, Kentucky and Arkansas. When it reaches the Mississippi it jogs around the southeast corner of Missouri and continues westward along a line of latitude. The original stretch of the Mason Dixon line is close to latitude 39, quite near to the old border claimed by Maryland. The line added later zig tags along the Ohio and then due west along a straight line that is half a degree north of latitude 30.

The original plan was very complex. A circle 24 miles wide was surveyed around the Delaware town of New Castle.   Another survey line ran due west from Cape Henlopen to Chesapcake Bay. From this base line another line was surveyed northward to brush the western side of the circle and meet the point marked below Philadelphia. The latitude at this junction became the East west boundary, Mason and Dixon's line between Pennsylvania and Maryland.