Blue Jacket or Weyapiersenwah (c. 1743 – c. 1810) was a war chief of the Shawnee people, known for his militant defense of Shawnee lands in the Ohio Country. Perhaps the preeminent American Indian leader in the Northwest Indian War, in which a pan-tribal confederacy fought several battles with the nascent United States, he was an important predecessor of the famous Shawnee leader Tecumseh.
Blue Jacket participated in Dunmore's War and the American Revolutionary War (allied with the British), always attempting to maintain Shawnee land rights. With the British defeat in the American Revolutionary War, the Shawnee lost valuable assistance in defending the Ohio Country. The struggle continued as white settlement in Ohio escalated, and Blue Jacket was a prominent leader of the resistance.
On November 3, 1791, the army of a confederation of Indian tribes, led by Blue Jacket and Miami Chief Little Turtle, defeated an American expedition led by Arthur St. Clair, governor of the Northwest Territory. The engagement, known as the Battle of the Wabash or as St. Clair's Defeat, was the crowning achievement of Blue Jacket's military career, and the most severe defeat ever inflicted upon the United States by Native Americans. Traditional accounts of the battle tend to give most of the credit for the victory to Little Turtle. John Sugden argues that Little Turtle's prominence is due in large measure to Little Turtle's self-promotion in later years.
Blue Jacket's triumph was short-lived. The Americans were alarmed by St. Clair's disaster and raised a new professional army, commanded by General Anthony Wayne. On August 20, 1794, Blue Jacket's confederate army clashed with Wayne at the Battle of Fallen Timbers, just south of present-day Toledo, Ohio. Blue Jacket's army was defeated, and he was compelled to sign the Treaty of Greenville on August 3, 1795, ceding much of present-day Ohio to the United States.
In 1805, Blue Jacket also signed the Treaty of Fort Industry, relinquishing even more of Ohio. In Blue Jacket's final years, he saw the rise to prominence of Tecumseh, who would take up the banner and make the final attempts to reclaim Shawnee lands in the Ohio Country.