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.
Florida in the American Civil War
In early May 1865, Edward M. McCook's Union division was assigned to re-establish Federal control and authority in Florida. On May 13, G. W. Scott surrendered the last active Confederate troops in the state to McCook. 
On May 20, General McCook read Lincoln's Emancipation Proclamation during a ceremony in Tallahassee, officially ending slavery in Florida. That same day, his jubilant troopers raised the U.S. flag over the state capitol building. Tallahassee was the penultimate Confederate state capital to rejoin the Union. Austin, Texas rejoined the next month.