This essay examines the dynamic between local institutions and allegiance during the American Revolution. It focuses on how committees of safety and the British army affected colonists’ behavior in Brookhaven, New York. Between 1775 and 1778, these New Yorkers’ allegiances ostensibly shifted as their wartime circumstances changed. In 1775, as Brookhaven’s committee of safety monitored colonists’ behavior, a significant number of its male inhabitants signed the Continental Association. Yet in 1778, surrounded by an intimidating military and political presence, an equally significant number took the oath of allegiance to King George III, including almost all the members of the township’s committee of safety. By comparing the behavior of Brookhaven’s committee of safety and colonists to those in other parts of New York, alongside those in Delaware, Massachusetts, New Hampshire, Pennsylvania, and Virginia, this essay concludes that the lived reality of war and local institutions are central to understanding how most people experienced the American Revolution.