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.
1820s
At the beginning of the 1820s, the United States stretched from the Atlantic Ocean through to (roughly) the western edge of the Mississippi basin, though Florida, Michigan, Wisconsin and all present-day states fully west of the Mississippi had yet to be granted statehood. Two states were admitted to the union during this decade: Maine in 1820, and Missouri in 1821. The Adams–Onís Treaty, signed in 1819 and ratified by Spain in 1821, ceded Florida to the United States, and established a boundary between New Spain and the United States.