Florida's admission to the Union came after Spain ceded the territory to the United States in 1821 and after two brutal wars against the Seminole nation, who resisted removal from their ancestral lands. Statehood cemented Florida's entry as a slave state, part of the delicate sectional balance in Congress preceding the Civil War.
Florida's path to statehood was soaked in conflict. Spain had ceded the peninsula to the U.S. in 1821, but American control provoked fierce resistance from the Seminole people, who fought two long wars—including the brutal Second Seminole War from 1835 to 1842, one of the costliest Indian wars in U.S. history—rather than accept forced removal to Oklahoma.
When statehood finally came in 1845, it was engineered as part of a sectional balancing act: Florida entered as a slave state, paired in Congress with the admission of free-soil Iowa the following year, a pattern meant to preserve equilibrium between North and South that would ultimately collapse into civil war.
The new state's population was still concentrated along the coasts and in the north; much of the interior, including the vast Everglades, remained largely unmapped and inhabited by Seminole holdouts who had refused every treaty—descendants of whom proudly note their nation never formally surrendered.