(July 3, 1778), during the American Revolution, the killing of 360 American settlers in the Wyoming Valley of Pennsylvania, part of the stepped-up British campaign of frontier attacks in the West.

In early June, Colonel John Butler led a force of 1,000 loyalists (loyalist) and Iroquois allies against the 5,000 inhabitants of the valley—mostly American women and children gathered at Forty Fort. About 300 men and boys left the protection of the fort to meet the attackers. In the massacre that followed, 360 men, women, and children lost their lives, and many others who escaped to the forests died of starvation or exposure. Butler's forces then moved northward to continue the raids along the frontier settlements of New York, eventually leading to a more aggressive American action against the Iroquois.