Many of our state borders are segments of borders that date from England's and, later, the United States' territorial acquisitions, and they can be identified by looking for lines that provide multistate borders.
The French and Indian War Border
The French and Indian War (1754-63) resulted in the oldest of these multistate boundaries. In this war, England and her American colonists began what became the dismantling of France's possessions in North America. With this victory, England added to her North American possessions all the land between the Ohio River and the Mississippi River. The boundaries of that war are still on the map today, for they provide borders for the states of Ohio, Indiana, Illinois, and Wisconsin. (Figure 4)
The division of this land acquired in the French and Indian War influenced virtually every state border that followed. After the Revolution, Congress had to decide how best to divide this region, known as the Northwest Territory, into states. Congress assigned Thomas Jefferson the task of studying this matter and in 1784 Jefferson issued a report to Congress in which he proposed that the region be divided into states having two degrees of height and four degrees of width, wherever possible.
As it turned out, Congress didn't employ these borders when it enacted the Northwest Ordinance in 1787, the law that included the boundary lines for the future states to be created from the Northwest Territory. Congress did, however, adopt its underlying principle: All states should be created equal.
The Louisiana Purchase Borders
Probably the most notable American boundary is the long straight line that defines so much of the nation's northern border with Canada. This line is the 49th parallel. It first surfaced on the American map following the 1803 Louisiana Purchase. The document conveying France's remaining North American land — a tract that included all or some of Louisiana, Arkansas, Oklahoma, Missouri, Kansas, Iowa, Nebraska, South Dakota, Wyoming, Minnesota, Montana, and Colorado — states that the French Republic cedes to the United States "the Colony or Province of Louisiana with the same extent that it now has." This wording seems refreshingly brief and to the point for a legal document, if a bit vague. The vagueness is also the reason very little evidence of the Louisiana Purchase can be found in our state lines. Other than the boundaries provided by the Gulf of Mexico and the Mississippi River, no one knew what its boundaries were! Jefferson believed that all the land comprising the watershed leading to the Missouri and Mississippi rivers constituted the Louisiana Purchase. But, as he soon discovered, the United States' neighbors did not. In reality, France's American territory extended to the west as far as a Frenchman could go without getting shot by a Spaniard, and likewise to the north without getting shot by an Englishman. (Figure 5)
The ambiguous borders of the Louisiana Purchase led England and the United States to negotiate where France's former lands ended and where British North America (Canada) began. Under the Convention of 1818, the two nations agreed upon the 49th parallel from the westernmost longitude of Lake of the Woods to the crest of the Rocky Mountains. (Figure 6)
But the choice of the 49th parallel begs the question, why not 50? It's such a nice round number. The reason for the one-degree difference is that England needed to maintain her access to the Great Lakes via the westernmost of those lakes, Lake Superior. Such access was vital to England's fur trade in general and, in specific, to a major fur trading post located at the confluence of the Assiniboine and Red rivers — a place now known as...
'Give me the splendid irregularities any day. God bless the panhandles and notches, the West Virginias and Oklahomas.'