Most Native American tribes during the War of 1812 sided with British because they wanted to safeguard their tribal lands, and hoped a British victory would relieve the unrelenting pressure they were experiencing from U.S. settlers who wanted to push further into Native American lands in southern Canada and in the lower Great Lakes and the south. Although some tribes remained neutral and some supported the United States, the majority allied with Britain.
The Shawnee leader Tecumseh and his charismatic younger brother Tenskwatawa, a religious revivalist known as The Prophet, spearheaded a movement for Native American political and military unity to resist settler encroachment. When war began, Tecumseh persuaded activist warriors from tribes like the Fox, Chickamauga, Iroquois, Kickapoo, Mascouten, Mohawk, Ojibway, Piankeshaw, Potawatomi, Sauk and Shawnee to form an alliance to aid the British.This confederation supplied vital support to British forces on the western frontier and in Canada, notably in forcing surrenders of U.S. outposts on Mackinac Island and Detroit and aiding British victories at Queenston Heights and Beaver Dams in Ontario. After Tecumseh was killed in October 1813 at the Battle of the Thames in Upper Canada, the alliance began to fall apart, considerably diminishing the power of Native Americans east of the Mississippi to retain their homelands.
In western Georgia and eastern Mississippi Territory (now Alabama), General Andrew Jackson's forces defeated factions in the Creek Nation's ongoing civil war that opposed expansion of U.S. settlements in Creek territory, raising Jackson's national profile and forcing the Creeks to negotiate a peace treaty. The resulting Treaty of Fort Jackson compelled the Creeks to surrender about 23 million acres (most of southern Georgia and half of present-day Alabama) to the United States.- whitehouse history.org
