George Rogers Clark was an American military officer and surveyor from Virginia who became the highest-ranking Patriot military officer on the northwestern frontier during the Revolutionary War. He served as leader of the Virginia militia in Kentucky throughout much of the war. He is best known for his captures of Kaskaskia in 1778 and Vincennes in 1779 during the Illinois campaign, which greatly weakened British influence in the Northwest Territory and earned Clark the nickname of "Conqueror of the Old Northwest". The British ceded the entire Northwest Territory to the United States in the 1783 Treaty of Paris.

The Illinois campaign, also known as Clark's Northwestern campaign, was a series of engagements during the American Revolutionary War in which a small force of Virginia militia led by George Rogers Clark seized control of several British posts in the Illinois Country of the Province of Quebec, located in modern-day Illinois and Indiana in the Midwestern United States. The campaign is the best-known action of the western theater of the war and the source of Clark's reputation as an early American military hero.