The Battle of Groton Heights was a battle of the American Revolutionary War fought on September 6, 1781, between a small Connecticut militia force led by Lieutenant Colonel William Ledyard and the more numerous British forces led by Brigadier General Benedict Arnold and Lieutenant Colonel Edmund Eyre. In an unsuccessful attempt to divert General George Washington from marching against Lord Cornwallis's army in Virginia, Lieutenant General Sir Henry Clinton ordered General Arnold to raid the Connecticut port of New London. Although the raid was a success, the Connecticut militia stubbornly resisted British attempts to capture Fort Griswold, across the Thames River in Groton. Several leaders of the attacking British force were killed or seriously wounded, and much of the defending garrison was either killed, mortally wounded, or captured when the fort was stormed. High British casualties lead to criticism of General Arnold by some of his superiors. The battle was the last major military encounter of the war in the northern United States, preceding the decisive American victory at Yorktown, Virginia, by about six weeks.