Mason & Dixon: Their Line And Its Legend


Lines on maps may be drawn by engineers, but they are interpreted by political events. Seldom has history recorded an amicable and abiding acceptance of such demarcations when they involve restless dynastic movements, whether the example be Pope Alexander VI’s division of the New World in 1493 between Spain and Portugal, or the twentieth century’s unhappy establishment of the border between East and West Berlin after World War II. The surveyor’s work becomes a symbol, and his name may become a catch phrase for a congeries of political and social issues of which he never dreamed.

The prime illustration of such an event in the United States is the line laid out for a total of about 332 miles by two English astronomer-surveyors between 1763 and 1767, to settle a dispute between the Perms and the Baltimores. For more than eighty years these powerful proprietaries had contended over the precise location of their common border. When they finally settled upon these two scientists to direct an impersonal, mathematically dependable survey, they set the stage for an engineering feat of impressive dimensions for that time.

But Charles Mason and Jeremiah Dixon were destined to be remembered for their substantial engineering and scientific accomplishments only in the annals of specialists. Mason, among other things, later completed a catalogue of 387 stars, which, when incorporated into a nautical almanac published in 1787, became the standard authority on the subject for a number of years. Dixon, a county surveyor and amateur astronomer, was considered sufficiently adept in his field to be elected to the Royal Society. He took part in several overseas scientific expeditions for the Society.”

For considerably more than a century, however, what the average American has understood by the Mason-Dixon survey has been a figurative division between two frames of reference in national life. Just as the South—and, for that matter, the North—tended to become a state of mind, so the Mason-Dixon Line has come to be viewed only incidentally as a real border and more as a line of transition between these two states of mind. In the national psychology it is thought of as a jagged extension of the border between Pennsylvania and Maryland to some vaguely defined point on the Missouri-Kansas border.

Just when this popular concept first took shape is not easy to say. Obviously, as sectional consciousness in the matter of slavery increased in the first half of the nineteenth century, the fact that Maryland, the most northerly slave state, was divided from Pennsylvania’s free soil by the Mason-Dixon survey impressed itself upon the public mind. The Ohio River, as the border between the southern state of Kentucky and the Northwest Territory, where slavery was prohibited, was a natural landmark extending the symbolism of the Mason-Dixon Line, the western terminus of which lay close to that great waterway to the West. Finally, the Missouri Compromise, fixing the northern limit of slave territory at latitude 36 degrees 30 minutes north, westward from the Ohio’s juncture with the Mississippi, completed the popular image.

The issues which thus developed in the nineteenth century around Mason and Dixon’s survey, and made their names a household phrase, have largely obscured the significant political and scientific results of the original project. That project—a border settlement of the eighteenth century—in turn traced its beginnings to issues which arose in the seventeenth century, and even earlier. The problem really started with England’s belated decision to launch her own colonizing efforts in the New World, where Spain and Portugal had long preceded her and where she now found the Netherlands, Sweden, and France in close competition.

Sir Walter Raleigh made the first colonization attempt at Roanoke Island in 1585. After failure of this effort the Virginia Companies of London and Plymouth were chartered, and founded the first two permanent English settlements—at Jamestown in 1607, and at Plymouth in 1620. Unfortunately, James I fixed the northernmost limit of the London Company at latitude 41 degrees north and the southernmost limit of the Plymouth Company at 38 degrees north—an overlap that included more than half of what is now Pennsylvania and New Jersey, and all of Maryland. Within this overlapping area, however, neither company was to settle within 100 miles of the other. This arrangement did, in fact, avoid most arguments between the first and second English colonies; but it multiplied the difficulties for those who came after and settled in between.

One of these was George Calvert, the first Lord Baltimore, whose Maryland charter was granted in 1632. In the course of the next fifty years his heirs were able, in various ways, to overcome claims made by the Dutch, the Virginians, and the Swedes. But the real trouble began only after Charles II’s grant of Pennsylvania to William Penn in 1681, and a subsequent grant to Penn by James, Duke of York, of land extending south as far as Chesapeake Bay.