American Revolutionary War: King George III delivers his Proclamation of Rebellion to the Court of St James's stating that the American colonies have proceeded to a state of open and avowed rebellion.

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.

George III was King of Great Britain and Ireland from 25 October 1760 until his death in 1820. The Acts of Union 1800 unified Great Britain and Ireland into the United Kingdom of Great Britain and Ireland, with George as its king. He was concurrently Duke and Prince-elector of Hanover in the Holy Roman Empire before becoming King of Hanover on 12 October 1814. He was the first monarch of the House of Hanover who was born in Great Britain, spoke English as his first language, and never visited Hanover.

The Proclamation of Rebellion, officially titled A Proclamation for Suppressing Rebellion and Sedition, was the response of George III to the news of the Battle of Bunker Hill at the outset of the American Revolutionary War. Issued on 23 August 1775, it declared elements of the American colonies in a state of "open and avowed rebellion". It ordered officials of the empire "to use their utmost endeavours to withstand and suppress such rebellion". The 1775 proclamation of rebellion also encouraged subjects throughout the empire, including those in Britain, to report anyone carrying on "traitorous correspondence" with the rebels to be punished.