Maritime history of Florida
Spain ceded Florida to the United States as part of the Adams–Onís Treaty of 1819, and Florida became a U.S. territory in 1821. Coastal trade with other markets continued to expand and towns like Jacksonville, Pensacola and Tampa became important ports. After becoming a U.S. territory, the federal government began building a series of lighthouses as aids to navigation along the coasts of Florida to mark dangerous headlands, shoals, bars and reefs.
Florida Territory
[195 U.S. 138, 142] 'This treaty is the law of the land, and admits the inhabitants of Florida to the enjoyment of the privileges, rights, and immunities of the citizens of the United States. It is unnecessary to inquire whether this is not their condition, independent of stipulation. They do not, however, participate in political power; they do not share in the government till Florida shall become a state. In the meantime Florida continues to be a territory of the United States, governed by virtue of that clause in the Constitution which empowers Congress 'to make all needful rules and regulations respecting the territory or other property belonging to the United States."