Battle of Wyoming - Wikipedia

On July 3, 1778, British forces massacre 300-360 men in Wyoming, Pennsylvania. From the article:

"The British forces arrived in the valley on June 30, having alerted the settlers to their approach by killing three men working at an unprotected gristmill on June 28. The next day Colonel Butler sent a surrender demand to the militia at Wintermute's (Wintermoot) fort. Terms were arranged that the defenders, after surrendering the fort with all their arms and stores, would be released on the condition that they not again bear arms during the war. On July 3, however, the British saw that the defenders were gathering in great numbers outside of Forty Fort. William Caldwell was engaged in destroying Jenkin's fort, and with the American militia a mile away, Butler organized an ambush. He ordered Fort Wintermute set on fire, and the Patriots, believing it signified a British retreat, advanced rapidly. Butler told the Seneca to lie flat on the ground so as not to be seen. The militia advanced to within a hundred yards of the British rangers and fired three volleys at them. The Seneca rose to their feet, fired one time, and then charged the militia to engage in hand to hand combat.

Accounts indicate the battle lasted about 45 minutes. An order to reform the Patriot line instead turned into a frantic rout as the inexperienced militiamen panicked and began to run. It became a deadly footrace, from which only about sixty Patriots escaped. The victorious Loyalists and Iroquois killed almost all who were captured, and only 5 prisoners were taken alive. Butler reported that 227 scalps were taken by his Native American allies.[7]

The next morning Colonel Nathan Denison agreed to surrender Forty Fort and two other posts, along with what remained of his militia. Butler paroled them on their promise to take no part in further hostilities. Non-combatants were spared and only a few inhabitants were molested after the forts' surrender.[8]

Colonel Butler wrote: "But what gives me the sincerest satisfaction is that I can, with great truth, assure you that in the destruction of the settlement not a single person was hurt except such as were in arms, to these, in truth, the Indians gave no quarter."[9] An American farmer wrote: "Happily these fierce people, satisfied with the death of those who had opposed them in arms, treated the defenseless ones, the woman and children, with a degree of humanity almost hitherto unparalleled".[10] Nevertheless, Colonel Denison and his men did not honor their parole, and within the year they would participate in attacks on Iroquois villages.

According to one source, 60 Patriot bodies were found on the battlefield and another 36 on the line of the retreat. All were buried in a common grave."