Florida Territory
Beginning in late 1835, Osceola and the Seminole allies began a guerrilla war against the U.S. forces. Numerous generals fought and failed, succumbing to the heat and disease as well as lack of knowledge of the land. It was not until General Thomas Jesup captured many of the key Seminole chiefs, including Osceola who died in captivity of illness, that the battles began to die down. The Seminoles were eventually forced to migrate. Florida joined the Union as the 27th state on March 3, 1845. By this time, almost all of the Seminoles were gone, except for a small group living in the Everglades.
West Florida
Because of disagreements with the Spanish government, American and English settlers between the Mississippi and Perdido rivers declared that area as the independent Republic of West Florida in 1810. (None of the short-lived Republic lay within the borders of the modern U.S. state of Florida; it comprised the Florida parishes of today's Louisiana.) Within months it was annexed by the United States, which claimed the region as part of the Louisiana Purchase of 1803. In 1819 the United States negotiated the purchase of the remainder of West Florida and all of East Florida in the Adams–Onís Treaty, and in 1822 both were merged into the Florida Territory.