United States territorial acquisitions
West Florida was declared to be a U.S. possession in 1810 by President James Madison after the territory had declared its independence from Spain. Madison ordered the U.S. Army to take control. Six weeks later, the army entered and occupied the capital, St. Francisville, putting an end to the republic after 74 days of independence. Spain did not relinquish its claim to sovereignty (see West Florida Controversy) until ratification of the Adams–Onís Treaty. General Andrew Jackson personally accepted the delivery of West Florida from its Spanish governor on July 17, 1821.
Everglades
In 1817, Andrew Jackson invaded Florida to hasten its annexation to the United States, in what became known as the First Seminole War. After Florida became a U.S. territory in 1821, conflicts between settlers and the Seminole increased as the former tried to acquire lands. The Second Seminole War lasted from 1835 to 1842, and afterward, the US forcibly removed about 3,000 Seminole and 800 Black Seminole to Indian Territory (now Oklahoma), west of the Mississippi River. Many others died in the war. Conflict broke out again in the Third Seminole War from 1855 to 1859, when a few hundred Seminole fought off US forces from the swamps of the Everglades. The US finally decided to leave them alone, as they could not dislodge them even after this protracted and expensive warfare.