Westsylvania was an unsuccessful attempt to create a 14th state during the Revolutionary War period, the successor to several previous attempts to establish governments in the western mountains. Much of the history of trans-Allegheny Virginia (now West Virginia) was influenced by competition for control of the huge expanses of land which had been awarded to speculators. The situation was complicated by grants of the same land to groups of investors and then further complicated by "squatters" who moved into Western Virginia, western Pennsylvania, and Ohio, made improvements on the land, and then attempted to file legitimate claims on their farms.

In the 1770s, a large group of investors had tried to establish control over the region by promoting the formation of a new colony, Vandalia. That effort failed because Pennsylvania and Virginia disputed ownership of much of the region and because of the growing rift between the colonists and England, which led to the Revolutionary War. A new effort to achieve the same goal was put forth in the summer of 1776 when the Continental Congress was asked to approve the creation of Westsylvania as a new commonwealth, a step toward the creation of a 14th state. The proposed state would have included all of trans-Allegheny Virginia and substantial parts of western Pennsylvania and eastern Ohio. According to historian Otis K. Rice, prime movers in the scheme were likely Benjamin Franklin, George Morgan, and Samuel and Thomas Wharton. While such investors were politically powerful, they were opposed by equally powerful interests, and once again conflicting claims from Virginia and Pennsylvania doomed the proposal.