Florida
Florida had become a burden to Spain, which could not afford to send settlers or garrisons. Madrid therefore decided to cede the territory to the United States through the Adams–Onís Treaty, which took effect in 1821. President James Monroe was authorized on March 3, 1821 to take possession of East Florida and West Florida for the United States and provide for initial governance. Andrew Jackson, on behalf of the U.S. federal government, served as a military commissioner with the powers of governor of the newly acquired territory for a brief period. On March 30, 1822, the U.S. Congress merged East Florida and part of West Florida into the Florida Territory.
By the early 1800s, Indian removal was a significant issue throughout the southeastern U.S. and also in Florida. In 1830, the U.S. Congress passed the Indian Removal Act and as settlement increased, pressure grew on the U.S. government to remove the Indians from Florida. Seminoles offered sanctuary to blacks, and these became known as the Black Seminoles, and clashes between whites and Indians grew with the influx of new settlers. In 1832, the Treaty of Payne's Landing promised to the Seminoles lands west of the Mississippi River if they agreed to leave Florida. Many Seminole left at this time.
History of Florida
Following Abraham Lincoln's election in 1860, Florida joined other Southern states in seceding from the Union. Secession took place January 10, 1861, and, after less than a month as an independent republic, Florida became one of the founding members of the Confederate States of America. As Florida was an important supply route for the Confederate Army, Union forces operated a blockade around the entire state. Union troops occupied major ports such as Cedar Key, Jacksonville, Key West, and Pensacola. Though numerous skirmishes occurred in Florida, including the Battle of Natural Bridge, the Battle of Marianna and the Battle of Gainesville, the only major battle was the Battle of Olustee near Lake City.