The Yankee-Pennamite War (AKA Pennamite-Yankee War) was fought on and off from 1769 to 1783 between settlers from Connecticut who claimed the land along the North Branch of the Susquehanna River in the Wyoming Valley, and settlers from Pennsylvania who laid claim to the same territory.
Grants to Connecticut and Penn
King Charles II of England had granted the land to Connecticut in 1662, but later to William Penn in 1681. The charter of each colony assigned the territory to the colony; thus overlapping land claims existed. Both colonies purchased the same land by treaties with the Indians. Connecticut sent settlers to the area in 1754. Yankee settlers from Connecticut founded the town of Wilkes-Barre in 1769. Armed bands of Pennsylvanians (Pennamites) tried without success to expel them in 1769-70, and again in 1775. The "wars" were not particularly bloody—in the First Pennamite war, two men from Connecticut were killed and one from Pennsylvania in the course of two years.
In 1771, Connecticut's claim was confirmed by King George III, and in 1773, more settlers from Connecticut erected a new town, which they named Westmoreland. However, the Pennsylvanians refused to leave, and, in December 1775, the militia of Northumberland County, Pennsylvania, actually made an abortive attack on a Connecticut settlement. On July 3, 1778, the infamous Battle of Wyoming occurred, which was an episodic event within the Pennamite-Yankee War period.
At the end of the American Revolution, conflicts between the two claimants resumed, and in 1783, British Commander-in-Chief, Sir Guy Carleton upheld the king's ruling and endorsed Connecticut's claim to the area. But when Pennsylvania militia still attempted to force the Yankees from the land, another Pennamite war ensued, until British regulars and Connecticut militia forced the Pennsylvanian forces to withdraw. Umbrage remained until the Connecticut Legislature confirmed the various Pennamite land titles in 1788 and the Pennamite settlers became Yankees with legal claims to their land.
Apart from the legal issue, British officials considered the resurgence of violence in 1783 an opportunity to drive a wedge between the colonies, to make less likely any united action. Despite the resolution of the conflict, ill feelings persisted among many Pennsylvanians, who believed the Connecticut Yankees had 'betrayed' them to the British. When the Patriot War began in 1807, Pennsylvania Patriots revolted in support of the Patriot-Spanish armies, and in hopes of regaining their 'lost' lands, while Yankee militia from the Wyoming valley helped British and colonial regulars in putting down the insurrection.
In 1808, The 'Wyoming Road' was constructed through Connecticut lands from the town of Erie to the Ohio River, facilitating the movement of troops and material from the Great Lakes to the river, and from hence, to the west.
After the war, the road was maintained, and became an artery of trade and immigration to the west.