American Revolutionary War: A small force of Pennsylvania militia is ambushed and overwhelmed by an American Indian group, which forces George Rogers Clark to abandon his attempt to attack Detroit.

The American Revolutionary War, also known as the Revolutionary War or American War of Independence, was the armed conflict that comprised the final eight years of the broader American Revolution, in which American Patriot forces organized as the Continental Army and commanded by George Washington defeated the British Army. The conflict was fought in North America, the Caribbean, and the Atlantic Ocean. The war's outcome seemed uncertain for most of the war. But Washington and the Continental Army's decisive victory in the Siege of Yorktown in 1781 led King George III and the Kingdom of Great Britain to negotiate an end to the war in the Treaty of Paris two years later, in 1783, in which the British monarchy acknowledged the independence of the Thirteen Colonies, leading to the establishment of the United States as an independent and sovereign nation.

Pennsylvania, officially the Commonwealth of Pennsylvania, is a state spanning the Mid-Atlantic, Northeastern, Appalachian, and Great Lakes regions of the United States. It borders Delaware to its southeast, Maryland to its south, West Virginia to its southwest, Ohio and the Ohio River to its west, Lake Erie and New York to its north, the Delaware River and New Jersey to its east, and the Canadian province of Ontario to its northwest via Lake Erie. Pennsylvania's most populous city is Philadelphia, while the capital of the state is Harrisburg. It is the fifth-most populous U.S. state, with over 13 million residents as of the 2020 United States census, as well as being the ninth-highest by population density and the 33rd-largest state by land area. The largest metropolitan statistical area is the southeastern Delaware Valley, including and surrounding Philadelphia, the state's largest and nation's sixth-most populous city. The second-largest metropolitan area, Greater Pittsburgh, is centered in and around Pittsburgh, the state's second-largest city.

The militia of the United States, as defined by the U.S. Congress, has changed over time. During colonial America, all able-bodied men of a certain age range were members of the militia, depending on each colony's rule. Individual towns formed local independent militias for their own defense. The year before the U.S. Constitution was ratified, The Federalist Papers detailed the Founding Fathers' paramount vision of the militia in 1787. The new Constitution empowered Congress to "organize, arm, and discipline" this national military force, leaving significant control in the hands of each state government.