Wyoming Valley Massacre, a battle in eastern Pennsylvania during the Revolutionary War. On July 3, 1778, Colonel Zebulon Butler led some 360 men from Forty Fort in the Wyoming Valley to meet an invading force of about 1,100 Loyalists and Iroquois Indians commanded by Major John Butler. (The two Butlers were not related.) The outnumbered detachment was routed; almost all were killed in battle or later scalped, tortured, and then slain. Only Colonel Butler and about 60 others escaped; most returned to the fort. Forty Fort surrendered the next day under terms that would spare lives and property.

After the surrender, the Loyalists lost control of their Indian allies, who pillaged the fort and drove the settlers from the valley. In retaliation, General George Washington, in 1779, sent an expedition that destroyed Iroquois settlements in the area.