Tecumseh’s War or Tecumseh’s Rebellion was a conflict from August 12, 1810 to October 5, 1813 between the United States and Tecumseh’s Confederacy, led by the Shawnee leader Tecumseh in the Indiana Territory. Tecumseh’s War continued into the War of 1812, lasting two more years, until 1813, when Tecumseh and his second-in-command, Roundhead, died fighting General William Henry Harrison’s Army of the Northwest at the Battle of the Thames in Upper Canada, near present-day Chatham, Ontario, and his confederacy disintegrated.