1821 – Florida was officially transferred from Spanish to American control on this date. As part of the Adams – Onís treaty of 1818, both East and West Florida were ceded to the United States. Two flag ceremonies took place, the first of which was in St. Augustine on July 10th, and the second took place in Pensacola on July 17th. The population of the new territory was relatively small, although settlement would increase significantly during the territorial years (1821-1845) as the United States sought to incentivize settlement through the use of land grants. Florida would become the 27th state 24 years later on March 3rd, 1845.