The trouble started with the Mason-Dixon line. The famous survey, conducted between 1763 and 1767, settled the border between Pennsylvania and Maryland - but the surveyors were stopped by hostile Native American territory before they could extend the line all the way west. The line stayed unfinished until 1784. In the meantime, Pennsylvania and Virginia both claimed jurisdiction over the country around Pittsburgh. Pennsylvania called it part of Westmoreland County. Virginia called it the District of West Augusta. Both colonies appointed sheriffs. Both colonies collected taxes, when they could. Local farmers chose which government to obey based on convenience, ideology, or sometimes just on who showed up at the door.

In 1776, weary of the chaos and inspired by the revolutionary moment, residents of the disputed region drafted what they called The Memorial of the Inhabitants of the Country, West of the Allegheny Mountains. The document is one of the more remarkable pieces of revolutionary American political writing - a frank assessment of dysfunction combined with a confident assertion that the solution was a new state. The petitioners argued that the Pennsylvania-Virginia dispute would, in all probability, terminate in a civil war if Congress did not intervene. They warned of bloody Indian conflict if land speculators were allowed to keep encroaching on Native territory. And they asked, in formal 18th-century prose, that their country be 'declared & acknowledged a separate, distinct, and independent Province & Government by the Title and under the name of the Province & Government of Westsylvania.'

Westsylvania was not the first attempt to create a new colony in this country. Before the Revolution, the Ohio Company of Virginia and the Indiana Land Company - large speculator firms with vast paper claims along the Ohio - had combined as the Grand Ohio Company and lobbied the British government to recognize a new colony called Vandalia, with roughly the same boundaries Westsylvania would later propose. The plan made it as far as a 1773 royal assent before the outbreak of the Revolutionary War killed it. When Westsylvania came along three years later, it was, in effect, the same idea reborn under republican management. The geography wanted a new state. The geography did not get one.

Pennsylvania and Virginia finally settled their boundary dispute in 1780, drawing what would eventually become the modern state line. The settlement left some Virginians waking up to discover they were now Pennsylvanians, which they did not enjoy. Westsylvania sentiment revived. In 1782, the Pittsburgh lawyer Hugh Henry Brackenridge - a future Pennsylvania Supreme Court justice, and at the time a strong supporter of the central government - convinced the Pennsylvania Assembly to pass a remarkable law: advocating for a separate state was henceforth treason, punishable by death. Pennsylvania also sent secret agents into the western counties. The historian Jack Sosin records that the combination of the death penalty, the threat that settlers' land titles might be invalidated, and the cool reception from Congress 'finally quieted the Westerners.'

On the map, Westsylvania would have covered most of present-day West Virginia, all of southwestern Pennsylvania including Pittsburgh, slivers of Kentucky and Maryland, and a piece of the Virginia panhandle. Its capital would presumably have been Pittsburgh - the only town in the region with any pretension to urban status in 1776. Its economy would have been driven by river commerce on the Ohio and its tributaries. Its politics would have been dominated by the kind of western-republican populism that, twelve years later, produced the Whiskey Rebellion - a tax revolt in the same geography by many of the same families. West Virginia did finally get its statehood in 1863, on different terms and during a different war. But the idea was already 87 years old by then. Westsylvania has the distinction of being the longest-running unrealized state in American history, and the only one whose advocacy was once a capital crime.