A significant fraction of New York City burned in the early morning hours of September 21, 1776, six days after the British army had occupied the city during the Revolutionary War. This paper examines the evidence to determine the cause of the fire, and argues that Patriots were responsible. Loyalists and British military men were almost unanimous in their conviction that American rebels had torched the city on their way out, but the rebels insisted that the fire had been an accident. Before the fire, General Nathanael Greene argued that destroying the city was strategically essential, but the Continental Congress was unwilling to risk the new nation's reputation, and ordered General George Washington to leave the city intact. Since the war, American historians have accepted these denials (and subsequent Patriot propaganda) and avoided attributing the fire to Patriot spies or civilian sympathizers. Rather than admit to burning towns, the Patriots concealed their actions to contemporaries and for posterity.